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1. Creep enhancement and sliding in a temperate, hard-bedded alpine glacier

Author: J.-P. Roldán-Blasco, A. Gilbert, L. Piard, F. Gimbert, C. Vincent, O. Gagliardini, A. Togaibekov, A. Walpersdorf, and N. Maier
Subjects: Environmental sciences, GE1-350, Geology, QE1-996.5
Abstract: Glacier internal deformation is usually described by Glen's flow law using two material parameters: the creep factor (A) and the flow law exponent (n). However, the values of these parameters and their spatial and temporal variability are rather uncertain due to the difficulty in quantifying internal strain and stress fields at natural scales. In this study, we combine 1-year-long continuous measurements of borehole inclinometry and surface velocity with three-dimensional full-Stokes ice flow modeling to infer ice rheologies and sliding velocities for the ablation zone of the Argentière Glacier, a temperate glacier in the French Alps. We demonstrate that the observed deformation rate profile has limited sensitivity to the flow law exponent (n) and instead mainly reflects an increase in the creep factor (A) with depth, with A departing from its surface value by up to a factor of 2.5 below 160 m depth. We interpret this creep factor enhancement as an effect of increasing interstitial water content with depth (from 0 % to 1.3 %), which results in an average value of A=148 MPa−3 a−1. We further observe that internal ice deformation exhibits seasonal variability similar to that concerning surface velocity, indicating that the local basal sliding velocity exhibits no significant seasonal variation. We suggest that these changes in deformation rate are due to variations in the stress field, driven by contrasting changes in subglacial hydrology conditions between the sides and center of the glacier. Our study provides further evidence that borehole inclinometry, combined with full-Stokes flow modeling, allows for the constraining of both ice rheology and basal friction at scales that cannot be inferred from surface velocity measurements alone.
Published: 2025
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2. Present-day geodynamics of the Western Alps: new insights from earthquake mechanisms

Author: M. Mathey, C. Sue, C. Pagani, S. Baize, A. Walpersdorf, T. Bodin, L. Husson, E. Hannouz, and B. Potin
Subjects: Geology, QE1-996.5, Stratigraphy, QE640-699
Abstract: Due to the low to moderate seismicity of the European Western Alps, few focal mechanisms are available in this region to this day, and the corresponding current seismic stress and strain fields remain partly elusive. The development of dense seismic networks in past decades now provides a substantial number of seismic records in the 0–5 magnitude range. The corresponding data, while challenging to handle due to their amount and relative noise, represent a new opportunity to increase the spatial resolution of seismic deformation fields. The aim of this paper is to quantitatively assess the current seismic stress and strain fields within the Western Alps, from a probabilistic standpoint, using new seismotectonic data. The dataset comprises more than 30 000 earthquakes recorded by dense seismic networks between 1989 and 2013 and more than 2200 newly computed focal mechanisms in a consistent manner. The global distribution of P and T axis plunges confirms a majority of transcurrent focal mechanisms in the entire western Alpine realm, combined with pure extension localized in the core of the belt. We inverted this new set of focal mechanisms through several strategies, including a seismotectonic zoning scheme and grid procedure, revealing extensional axes oriented obliquely to the strike of the belt. The Bayesian inversion of this new dataset of focal mechanisms provides a probabilistic continuous map of the style of seismic deformation in the Western Alps. Extension is found to be clustered, instead of continuous, along the backbone of the belt. Robust indications for compression are only observed at the boundary between the Adriatic and Eurasian plates. Short-wavelength spatial variations of the seismic deformation are consistent with surface horizontal Global Navigation Satellite System (GNSS) measurements, as well as with deep lithospheric structures, thereby providing new elements with which to understand the current 3D dynamics of the belt. We interpret the ongoing seismotectonic and kinematic regimes as being controlled by the joint effects of far-field forces – imposed by the anticlockwise rotation of Adria with respect to Europe – and buoyancy forces in the core of the belt, which together explain the short-wavelength patches of extension and marginal compression overprinted on an overall transcurrent tectonic regime.
Published: 2021
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3. Geodetic point surface mass balances: a new approach to determine point surface mass balances on glaciers from remote sensing measurements

Author: C. Vincent, D. Cusicanqui, B. Jourdain, O. Laarman, D. Six, A. Gilbert, A. Walpersdorf, A. Rabatel, L. Piard, F. Gimbert, O. Gagliardini, V. Peyaud, L. Arnaud, E. Thibert, F. Brun, and U. Nanni
Subjects: Environmental sciences, GE1-350, Geology, QE1-996.5
Abstract: Mass balance observations are very useful to assess climate change in different regions of the world. As opposed to glacier-wide mass balances which are influenced by the dynamic response of each glacier, point mass balances provide a direct climatic signal that depends on surface accumulation and ablation only. Unfortunately, major efforts are required to conduct in situ measurements on glaciers. Here, we propose a new approach that determines point surface mass balances from remote sensing observations. We call this balance the geodetic point surface mass balance. From observations and modelling performed on the Argentière and Mer de Glace glaciers over the last decade, we show that the vertical ice flow velocity changes are small in areas of low bedrock slope. Therefore, assuming constant vertical velocities in time for such areas and provided that the vertical velocities have been measured for at least 1 year in the past, our method can be used to reconstruct annual point surface mass balances from surface elevations and horizontal velocities alone. We demonstrate that the annual point surface mass balances can be reconstructed with an accuracy of about 0.3 m of water equivalent per year (m w.e. a−1) using the vertical velocities observed over the previous years and data from unmanned aerial vehicle images. Given the recent improvements of satellite sensors, it should be possible to apply this method to high-spatial-resolution satellite images as well.
Published: 2021
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4. Rapid response to the M$_{\protect \rm w}$ 4.9 earthquake of November 11, 2019 in Le Teil, Lower Rhône Valley, France

Author: Cornou, Cécile, Ampuero, Jean-Paul, Aubert, Coralie, Audin, Laurence, Baize, Stéphane, Billant, Jérémy, Brenguier, Florent, Causse, Mathieu, Chlieh, Mohamed, Combey, Andy, de Michele, Marcello, Delouis, Bertrand, Deschamps, Anne, Ferry, Matthieu, Foumelis, Michalis, Froment, Bérénice, Gélis, Céline, Grandin, Raphaël, Grasso, Jean-Robert, Hannouz, Estelle, Hok, Sébastien, Jung, Axel, Jolivet, Romain, Langlais, Mickaël, Langlaude, Philippe, Larroque, Christophe, Leloup, Philippe Hervé, Manchuel, Kevin, Marconato, Léo, Maron, Christophe, Mathot, Emmanuel, Maufroy, Emeline, Mercerat, Diego, Metois, Marianne, Nayman, Emmanuelle, Pondaven, Ildut, Provost, Ludmila, Régnier, Julie, Ritz, Jean-François, Rivet, Diane, Schlupp, Antoine, Sladen, Anthony, Voisin, Christophe, Walpersdorf, Andrea, Wolynieck, David, Allemand, Pascal, Beck, Elise, Bertrand, Etienne, Bertrand, Véronique, Briole, Pierre, Brunel, Didier, Cavalié, Olivier, Chèze, Jérôme, Courboulex, Françoise, Douste-Bacque, Isabelle, Dretzen, Rémi, Giampietro, Tiziano, Godano, Maxime, Grandjean, Philippe, Grunberg, Marc, Guerin, Gauthier, Guillot, Stéphane, Haber, Elias El, Hernandez, Alain, Jomard, Hervé, Lasserre, Cécile, Liang, Chao, Lior, Itzhak, Martin, Xavier, Mata, Daniel, Menager, Marine, Mercier, Antoine, Mordret, Aurélien, Oral, Elif, Paul, Anne, Peix, Fabrice, Pequegnat, Catherine, Pernoud, Michel, Satriano, Claudio, Sassi, Rihab, Schaming, Marc, Sellier, Valérie, Sira, Christophe, Socquet, Anne, Sue, Christian, Trilla, Aurélie, Vallée, Martin, van den Ende, Martijn, Vernant, Philippe, Vial, Benjamin, and Weng, Huihui
Subjects: Le Teil earthquake, Rhône valley, Seismic sequence, Post-seismic, Surface rupture, InSAR interferometry, Geophysics. Cosmic physics, QC801-809, Chemistry, QD1-999, Geology, QE1-996.5
Abstract: On November 11, 2019, a M$_{\mathrm{w}}$ 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE–SW La Rouvière normal fault in reverse faulting in agreement with the present-day E–W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations), geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitor the temporal and spatial evolution of microearthquakes close to the fault plane and temporal evolution of the seismic response of 3 damaged historical buildings, and to study suspected site effects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by different institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakes along the major regional Cévenne fault system in a context of present-day compressional tectonics.
Published: 2021
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5. Geodetic point surface mass balances: a new approach to determine point surface mass balances on glaciers from remote sensing measurements

Author: Vincent Peyaud, Bruno Jourdain, Emmanuel Thibert, Florent Gimbert, Laurent Arnaud, Andrea Walpersdorf, Fanny Brun, Christian Vincent, Luc Piard, Diego Cusicanqui, Adrien Gilbert, Delphine Six, Antoine Rabatel, Olivier Laarman, Ugo Nanni, Olivier Gagliardini, Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Erosion torrentielle neige et avalanches (UR ETGR (ETNA)), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), French National Research Agency (ANR) European Commission, French National Research Agency (ANR) 18 CE1 0015 01, Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), ANR-18-CE01-0015,SAUSSURE,Glissement des glaciers et pression hydrologique sous glaciaire en relat(2018), and Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )
Subjects: 010504 meteorology & atmospheric sciences, Ice stream, Climate change, 010502 geochemistry & geophysics, 01 natural sciences, [SPI]Engineering Sciences [physics], Glacier mass balance, Point (geometry), [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, lcsh:Environmental sciences, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Remote sensing, lcsh:GE1-350, geography, geography.geographical_feature_category, Bedrock, lcsh:QE1-996.5, Geodetic datum, Glacier, 15. Life on land, lcsh:Geology, 13. Climate action, [SDE]Environmental Sciences, Satellite, Geology
Abstract: Mass balance observations are very useful to assess climate change in different regions of the world. As opposed to glacier-wide mass balances, which are influenced by the dynamic response of each glacier, point mass-balances provide a direct climatic signal that depends on surface accumulation and ablation only. Unfortunately, major efforts are required to conduct in situ measurements on glaciers. Here, we propose a new approach that determines point surface mass balances from remote sensing observations. We call this balance the geodetic point surface mass balance. From observations and modelling performed on Argentière and Mer de Glace glaciers over the last decade, we show that the vertical ice flow velocity changes are small in areas of low bedrock slope. Therefore, assuming constant vertical velocities in time for such areas and provided that the vertical velocities have been measured for at least one year in the past, our method can be used to reconstruct annual point surface mass balances from surface elevations and horizontal velocities alone. We demonstrate that the annual point surface mass balances can be reconstructed with an accuracy of about 0.3 m w.e. a-1 using the vertical velocities observed over the previous years and data from Unmanned Aerial Vehicle images. Given the recent improvements of satellite sensors, it should be possible to apply this method to high spatial resolution satellite images as well.
Published: 2021
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6. Seismogenic potential of the High Durance Fault constrained by 20 yr of GNSS measurements in the Western European Alps

Author: Stéphane Baize, M Mathey, Andrea Walpersdorf, Christian Sue, A Deprez, CNRS, IRD, IFSTTAR, ISTerre, University Grenoble Alpes, University Savoie Mont Blanc , 38000 Grenoble, France (ISTERRE), Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Bureau d'évaluation des risques sismiques pour la sûreté des installations (IRSN/PSE-ENV/SCAN/BERSSIN), Service de caractérisation des sites et des aléas naturels (IRSN/PSE-ENV/SCAN), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), IRSN, and ANR-10-LABX-0056,OSUG@2020,Innovative strategies for observing and modelling natural systems(2010)
Subjects: Neotectonics, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, Dynamics and mechanics of faulting, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Transient deformation, Continental tectonics: extensional, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Seismicity and tectonics, Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Geochemistry and Petrology, GNSS applications, Geodetic instrumentation, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: SUMMARYDue to the steady moderate seismicity observed along the Briançon seismic arc, in the south-western French Alps, three temporary GNSS (Global Navigation Satellite System) surveys took place in 1996, 2006 and 2011, across a ∼50 × 60 km² wide area, to investigate the surface deformation field. The horizontal velocity field computed from these three surveys showed an east–west extension in the network. A fourth campaign was led in 2016, creating a 20 yr observation span, resulting in measurements which reach a sufficient accuracy to assess whether extension found within the Briançon network is localized onto any particular tectonic feature. Several faults in this area are known to be active normal faults. Assessing the localization of the deformation may lead to a better understanding of the active tectonics of the Alpine belt. To address this issue, a robust velocity field was computed from the combination of the different campaign and permanent GNSS data. Strain rate tensors were derived for the first time in this area on a 0.1 × 0.1 deg grid to assess the distribution of the deformation. The regional deformation appears localized in the Briançon area and reaches up to 20 ± 5 nanostrain yr−1 in the centre of the network. The observed velocities were projected on a profile across the network and compared with modelled interseismic deformation to characterize the behaviour of the major active faults known in the study zone. While a two-fault model provides the best fit to the data, a single fault model has only marginally higher residuals, with parameters which are more consistent with the seismotectonics of the region. The localization of the single modelled fault is consistent with the location of the High Durance Fault (HDF). Therefore, we used the known geological location of this structure as a priori information in a block model to compute a fault slip rate at the interface between the two blocks. The velocities on the interface indicate 0.4–0.5 mm yr−1 of extension, and therefore strain accumulates along the HDF throughout the seismic cycle. The geodetically derived fault slip rate is converted into an equivalent seismic moment release rate, which is consistent within its uncertainty bounds with the known historical and instrumental seismicity of the Briançon area.
Published: 2020
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7. Mesoscale GPS Zenith Delay assimilation during a Mediterranean heavy precipitation event

Author: X. Yan, V. Ducrocq, P. Poli, G. Jaubert, and A. Walpersdorf
Subjects: Science, Geology, QE1-996.5, Dynamic and structural geology, QE500-639.5
Abstract: The impact of assimilating Zenith Total delay (ZTD) observations from a mesoscale ground-based GPS network over Western Europe is evaluated for the heavy precipitation event of 5–9 September 2005 over Southern France. The ZTD assimilation is performed using a three dimensional variational data assimilation system at the 9.5-km horizontal resolution. Then using as initial conditions the 3DVAR analyses with and without assimilation of ZTD, we perform 2.4-km non-hydrostatic MESO-NH simulations. The results of the fine-scale simulations indicate that assimilation of ZTD help to improve the forecast of the tropospheric water vapour content and the quantitative precipitation forecast. We have also assessed through single observation experiments the influence of the formulation of the observation operator which is used to compute the model equivalent ZTD.
Published: 2008

8. Constant Slip Rate on the Doruneh Strike‐Slip Fault, Iran, Averaged Over Late Pleistocene, Holocene, and Decadal Timescales

Author: Edward J. Rhodes, R. Alastair Sloan, Alexander L. Thomas, Mohammad Mahdi Khatib, Fynn Clive, Erwan Pathier, Zahra Mousavi, Morteza Fattahi, Andrea Walpersdorf, Morteza Talebian, Richard Walker, and Nicholas Dodds
Subjects: strike-slip, Pleistocene, active tectonics, Iran, Strike-slip tectonics, Geophysics, Doruneh fault, Geochemistry and Petrology, bookshelf faulting, Constant (mathematics), slip rate variations, Seismology, Holocene, Geology, Slip rate
Abstract: Varying estimates of both present‐day strain accumulation and long‐term slip‐rate on the Doruneh left‐lateral strike‐slip fault, NE Iran, have led to suggestions that it exhibits large along‐strike and/or temporal changes in activity. In this paper, we make and compare estimates of slip‐rate measured using both geodesy and geomorphology, and spanning time periods ranging from decadal to 100 ka. To image the present‐day accumulation of strain we process seven years (2003‐2010) of data from six ENVISAT tracks covering the fault, with interferograms produced for 400 km‐long strips of data in order to image the long‐wavelength signals associated with interseismic strain accumulation across the locked fault. Our analysis shows that less than 4 mm/yr – and likely only 1‐3 mm/yr ‐ of slip accumulates across the fault. Using high‐resolution optical satellite imagery we make reconstructions of displacement across six alluvial fans whose surfaces cross the fault, in four separate river catchments. We determine the ages of these fans using infra‐red‐stimulated luminescence dating combined with U‐series dating of pedogenic carbonates. The six fans vary in age from ∼10‐100 kyr, and a regression line fitted to four of these yields a slip rate of 2.5 ± 0.3 mm/yr. We conclude that within the uncertainty of our measurements the slip‐rate has remained constant over the last ∼100 ka and is representative of the strain accumulation at the present‐day. The slip‐rate that we measure is consistent with the E‐W left‐lateral Doruneh fault accommodating N‐S right‐lateral faulting by 'bookshelf' faulting, with clockwise rotation about a vertical axis.
Published: 2021
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9. Spatial Heterogeneity of Uplift Pattern in the Western European Alps Revealed by InSAR Time Series Analysis

Author: Christian Sue, Marguerite Mathey, Marie-Pierre Doin, Andrea Walpersdorf, Pauline André, and Stéphane Baize
Subjects: GNSS applications, Levelling, Interferometric synthetic aperture radar, Time series, Geodesy, Surface deformation, Geology, Spatial heterogeneity
Abstract: The western European Alps display measurable surface deformation rates from levelling and GNSS data. Based on the time series analysis of 4 yrs of Sentinel-1 data, we propose for the first time an ...
Published: 2021
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10. Basal speed and deformation velocity in an alpine temperate glacier from high resolution borehole tilt measurements and GNSS surface velocity observations

Author: Olivier Gagliardini, Juan Pedro Roldan-Blasco, Luc Piard, Christian Vincent, Adrien Gilbert, Andrea Walpersdorf, Anuar Tobaigekov, and Florent Gimbert
Subjects: Tilt (optics), GNSS applications, Temperate glacier, Borehole, High resolution, Deformation velocity, Surface velocity, Geodesy, Geology
Abstract: Basal sliding speed is a main component of glacier flow. However, acquiring direct observations of the velocity at the base of a glacier is a challenging task due to limited accessibility. One option consists in indirectly measuring basal speed by subtracting the internal deformation velocity from the velocity observed at the surface. Internal deformation has been mostly studied through annual surveys of borehole inclinometry that provide a snapshot of the internal velocity field of the glacier, while more recent efforts have installed continuously recording sensors at different depths. The former method provides a good resolution in depth, while the latter provides a good resolution in time, but few studies have provided both.In this study we quantify basal speed variations at both short and long timescales through the combined analysis of one year of continuous half-hour sampled borehole tilt measurements and high resolution GNSS positioning. The instrumentation campaign has been done in the framework of the SAUSSURE project, in which we drilled five boreholes in the ablation area of Argentière Glacier, a temperate mountain glacier in the French Alps. The boreholes were positioned along the center flow line, and each one was equipped with an array of ~18 sensors that recorded the tilt and azimuth at different depths as well as water pressure at the bottom and middle depth. With this dataset we are able to investigate how melt season impacts the internal dynamics of the glacier, or how the sudden accelerations of the glacier after heavy storms events are shared between changes in internal deformation and basal speed ups. We find that the yearly averaged internal deformation profile can be well described using a two dimensional Glen flow law with exponent n ~ 3.4. We observe as well that deformational velocities can represent up to 60% of the total velocity, more than previously considered for Argentière Glacier. Our findings suggest that weekly accelerations, usually observed along raises in water pressure, are due to the increase of basal speed paired with a decrease in deformation, which suggests stress reconfiguration. We don’t observe journal cycles of deformation velocity, which would indicate that journal variations of glacier velocity are due only to changes of basal speed. In contrast, glacier acceleration during melt season at monthly timescales is accommodated by deformation velocity and not by sliding.
Published: 2021
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11. Up to date geodetic velocity field of the Belledonne region (Western Alps, France)

Author: Estelle Hannouz, Christian Sue, Marguerite Mathey, Stéphane Baize, Anne Lemoine, Andrea Walpersdorf, and Sciencesconf.org, CCSD
Subjects: [SDU] Sciences of the Universe [physics], Active tectonic, Geodetic datum, Vector field, French Alps, Geodesy, Geology
Abstract: The Belledonne region, located on the western edge of the French Alps, behaves as a deformation transfer zone between the inner part of the western Alps, where geodesy and seismicity show extensional deformation, and its compressional surrounding basin (the Rhône Valley). Seismological and geodetic networks are less dense and younger in the Rhône Valley, which makes it more difficult to characterize its deformation. Nevertheless, these two regions have a moderate historical and instrumental seismicity. A large part of these earthquakes is concentrated on the Belledonne range and accommodated by the active NE–SW Belledonne fault, located at the western foot of this chain. The fault characteristics, such as its connection at depth with surrounding fault systems (e.g. Cléry fault), still need better constraints. The dense seismological network present in the Alpine region has made it possible to highlight its dextral strike-slip kinematics. To complete these observations, we present here an update of the geodetic velocity field around this fault from GNSS data recorded over the last two decades.To do so, we first computed daily positions for a total of about 200 stations provided by different European networks (IGS, RENAG, RGP, GAIN, DGFI networks) over a period of 23 years (from 1997 to 2020), by using a double-difference processing with the GAMIT software (Herring et al. 2015). Then, we constrained a velocity field with the Kalman filter GLOBK with respect to the fixed European plate. We finally analyzed the residual motions in our area of interest with respect to stable Europe, as provided by our updated velocity field.Across the Belledonne range, our results show a deformation pattern consistent with the dextral strike-slip mechanism observed by the current seismicity. Methodological studies concern the expected decrease of uncertainty on the velocity field thanks to the increase of recordings through time. These tests aim at quantifying the Belledonne fault present-day slip rate, including a well-constrained velocity uncertainty. We also exploit the new 3D velocity field to confirm and precise the local amplitude, in the Belledonne area, of the general uplift of the Alpine belt, as observed by previous geodetic studies.
Published: 2021
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12. Three-dimensional surface velocity variations of the Argentière glacier (French Alps) monitored with a high-resolution continuous GNSS network

Author: Christian Vincent, Laurent Ott, Agnès Helmstetter, Olivier Laarman, Benoit Urruty, Florent Gimbert, Andrea Walpersdorf, Ugo Nanni, Jean-Louis Mugnier, Delphine Six, Jean-Noël Bouvier, Luc Moreau, Christian Sue, Anuar Togaibekov, Olivier Romeyer, Mathilde Radiguet, Juan Pedro Roldan-Blasco, Marguerite Matthey, Luc Piard, and Stéphane Mercier
Subjects: geography, geography.geographical_feature_category, GNSS applications, Resolution (electron density), Glacier, Surface geometry, Geodesy, Geology
Abstract: Glacier dynamics exhibits a strong variability in response to climate forcing. To better understand the effects of this forcing, it is essential to provide continuous deformation measurements that must be long-term (over a full or several melt seasons) and high-resolution (from daily to sub-daily). GNSS monitoring represents a valuable mean to better apprehend mechanisms of basal sliding and provide high-resolution 3D constraints on physical models of glacier flow. In this study, we investigate motions and deformations of the Argentière Glacier in the French Alps at 2400 m altitude, derived from up to 12 permanent GNSS stations continuously operating since April 2019, covering two melting seasons. The Argentière glacier is particularly interesting due to (i) its long-term subglacial observatory measuring basal sliding velocity and subglacial discharge, and (ii) the wide range of complementary observations currently being acquired there, which give access to internal ice deformation thanks to tiltmeters in boreholes, and to basal stick-slip and englacial fracturing thanks to seismic observations. We present the results (i) over relatively long timescales (days to months) using the fast static positioning approach to evaluate mean variations and compare to the independent measurements mentioned above, and (ii) kinematic approach to focus on high temporal resolution velocity variations during specific short-term events that cannot be seen from the static processing. The horizontal surface velocities on daily time scales reveal spring acceleration due to meltwater followed by steadily high velocities over the summer, and significant episodic accelerations in the fall in response to the storm events. We quantify strain rates and their evolution in time that can be related to the vertical surface motions. We combine the GNSS with the englacial tiltmeters results to deduce the basal speed variations. The GNSS confrontation with other independent observations also allows analyzing the surface motions that combine horizontal speed-ups with uplift due to bed separation of the ice sheet. We will further search for evidence for surface motions that might occur in daily cycles in summer, as hinted at by the basal sliding measurements. But before analyzing daily cycles of glacier motions, it is critical to remove positioning artefacts due to multipath effects with a repeat period close to 24 hours. These effects are enhanced on the Argentière Glacier by the limited number of visible satellites in the narrow valley. Moreover, it evolves with the dynamically changing environment (snow accumulation and snowmelt that create variations in ground reflectivity properties). A multi-GNSS analysis combining GPS and GLONASS data helps overcome the lack of satellite data and increase the time resolution on a sub-daily scale. If daily cycles are resolvable from the improved GNSS analysis, their phase offsets with respect to meteorological, hydrological and seismic observations can give us indices of eventual mechanisms of sliding at the bedrock interface.
Published: 2021
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13. Seismotectonics of the Western Alps: new insights on seismogenic source characterization

Author: Christian Sue, Marguerite Mathey, Colin Pagani, Estelle Hannouz, Bertrand Potin, Andrea Walpersdorf, Stéphane Baize, Thomas Bodin, and Laurent Husson
Subjects: Source characterization, Seismotectonics, Seismology, Geology
Abstract: Due to the low to moderate seismicity of the European Western Alps, few focal mechanisms are available to date in this region, and the corresponding current seismic stress and strain fields remain partly elusive. The development of dense seismic networks in the past decades now provides a substantial amount of seismic records down to low magnitudes. The corresponding data, while challenging to handle due to their amount and relative noise, represent a new opportunity to increase the spatial resolution of seismic deformation fields.The aim of this study is to assess spatial variations of the tectonic regimes and corresponding stress and strain fields, which will provide new insights into active seismic deformation in this area. The dataset comprises more than 30,000 earthquakes relocalized in a 3D crustal velocity model, and more than 2200 focal mechanisms newly computed in a consistent manner. We inverted this new set of focal mechanisms through several strategies, including a seismotectonic zoning scheme and a Bayesian inversion, which provides a probabilistic 3D reconstruction of the faulting style in the Western Alps. The global distribution of P and T axes plunges confirms a majority of transcurrent focal mechanisms in the overall alpine realm, combined with pure extension localized in the core of the belt. Extension is found clustered, instead of continuous along the backbone of the belt. Compression is robustly retrieved only in the Po plain, which lays at the limit between the Adriatic and Eurasian plates. High frequency spatial variations of the seismic deformation are consistent with surface horizontal GNSS measurements as well as with deep lithospheric structures, thereby providing new elements to constrain homogeneously deforming zones. We interpret the ongoing seismotectonic and kinematic regimes as being controlled by the joint effects of far-field forces –imposed by the counterclockwise rotation of Adria with respect to Europe- and of buoyancy forces in the core of the belt, which together explain the high frequency patches of extension and of marginal compression overprinted on an overall transcurrent tectonic regime.These results shed new lights on seismicity distribution and tectonic regime variations both regionally and at depth. They appear complementary to geodetic constraints on active faults and to existing structural studies, thus allowing us to bring new insights into future seismogenic zoning schemes.
Published: 2021
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14. Spatio-temporal slip rate variability of the Doruneh fault (eastern Iran) from dense GNSS and SENTINEL data and a tectonic study

Author: F. Tavakoli, Marie-Pierre Doin, Y. Djamour, Zahra Mousavi, Erwan Pathier, Seied Abdolreza Saadat, Andrea Walpersdorf, Richard Walker, Fatemeh Khorrami, and Hamid Reza Nankali
Subjects: Tectonics, geography, geography.geographical_feature_category, GNSS applications, Fault (geology), Seismology, Geology, Slip rate
Abstract: The recent activity of the 600 km long E-W trending Doruneh fault in eastern Iran is attested by clear geomorphological features along its trace, while no instrumental earthquake can be related to this fault. The only two Mw7 events in this area took place on the Dasht-e Bayaz fault, south of Doruneh. The great length of the fault, the lack of the seismicity and the active regional N-S shortening induced by the Arabian-Eurasian convergence highlight the seismic potential of the Doruneh fault. However, until today, the short- and long-term slip rate estimates of the Doruneh fault remain controversial. Geomorphological offset dating indicates long-term slip rates between 2.5 mm/yr and 8.2 mm/yr. Preliminary GNSS measurements and local InSAR data reveal rates between 1 and 5 mm/yr. This wide range of slip rate estimates suggests either temporal or spatial variability of the Doruneh fault activity.To investigate the along-strike slip variability of the Doruneh fault, a dense GNSS survey including 18 sites has been conducted in 2012 and 2018. This network completes the 17 regional permanent GNSS stations. Combining campaign and permanent data, the horizontal GNSS velocity field constrains the slip velocity and its variability along the fault by complementary approaches, on profiles perpendicular to the fault, and by a rigid block model. Sinistral motion is maximal in the western part of the fault (1 to 4 mm/yr), and decreasing towards the east. A complementary InSAR velocity map based on Sentinel-1 images between 2014 and 2019 exploits two ascending tracks (A159 and A86) across the Doruneh fault. We followed the SBAS time series analysis approach and corrected the effects of annual loading cycles and tropospheric delay. Sand and unexpected large tropospheric effects prohibited correlation in some places, but a coherent mean velocity map in line of sight (LOS) direction to the satellites is obtained for most of our study area. This map shows no sharp variations along the fault trace that could indicate shallow fault creep. The clearest signals are zones of anthropogenic subsidence. Looking for a long-wavelength tectonic signal (less than 3 mm/yr spread over 100 km), we masked these areas of rapid and short-wavelength deformation. The resulting velocity maps for both tracks are projected on profiles perpendicular to the fault and indicate a long-wavelength signal across the Doruneh fault of less than 2 mm/yr in LOS direction. A systematic parameter search yields a first best fit on track A159 combining a horizontal slip rate of 3.25 mm/yr with a locking depth of 8 km in the western part of the fault. This approach will be pursued on track A86, covering the eastern part, after more thorough cleaning.We finally compare the combined GNSS-InSAR present-day fault slip rates to new long-term slip rates from geomorphological offset dating, to evaluate the time variability of the Doruneh fault activity. Our multi-disciplinary study will enhance our understanding of the Doruneh fault mechanism and its role in the kinematics of the Arabia-Eurasia collision, and contribute to a better seismic hazard assessment in eastern Iran.
Published: 2021
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15. Present-day uplift of the European Alps: Evaluating mechanisms and models of their relative contributions

Author: Pierre G. Valla, Laurent Jolivet, Carole Petit, Sean D. Willett, Sébastien Castelltort, Pietro Sternai, Andrea Walpersdorf, Jean-Mathieu Nocquet, Thorsten W. Becker, Laurent Husson, Giorgio Spada, Christian Sue, Andrea Di Giulio, Enrico Serpelloni, Claudio Faccenna, Sternai, Pietro, Sue, Christian, Husson, Laurent, Serpelloni, Enrico, Becker, Thorsten W., Willett, Sean D., Faccenna, Claudio, Di Giulio, Andrea, Spada, Giorgio, Jolivet, Laurent, Valla, Pierre, Petit, Carole, Nocquet, Jean-Mathieu, Walpersdorf, Andrea, Castelltort, Sébastien, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Roma (INGV), Istituto Nazionale di Geofisica e Vulcanologia, Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratory of Experimental Tectonics, Università degli Studi Roma Tre, Dipartimento di Scienze della Terra e dell'Ambiente [Pavia], Università degli Studi di Pavia, Dipartimento di Scienze di Base e Fondamenti, Università degli Studi di Urbino 'Carlo Bo', Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), University of Geneva, Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Department of Earth Sciences [ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Università di Pavia, Laboratoire de Géodynamique des Chaines Alpines (LGCA), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Sternai, P, Sue, C, Husson, L, Serpelloni, E, Becker, T, Willett, S, Faccenna, C, Di Giulio, A, Spada, G, Jolivet, L, Valla, P, Petit, C, Nocquet, J, Walpersdorf, A, and Castelltort, S
Subjects: European Alps Vertical displacement rate Deglaciation Erosion Lithospheric structural changes Mantle flow, Vertical displacement rate, 010504 meteorology & atmospheric sciences, European Alp, Present day, 010502 geochemistry & geophysics, 01 natural sciences, Paleontology, Lithospheric structural changes, Mantle convection, Lithosphere, Deglaciation, ddc:550, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Mantle flow, 15. Life on land, Lithospheric structural change, Tectonics, 13. Climate action, Erosion, Slab, General Earth and Planetary Sciences, Upwelling, European Alps, Earth and Planetary Sciences (all), Surface mass, Geology
Abstract: Recent measurements of surface vertical displacements of the European Alps show a correlation between vertical velocities and topographic features, with widespread uplift at rates of up to ~2–2.5 mm/a in the North-Western and Central Alps, and ~1 mm/a across a continuous region from the Eastern to the South-Western Alps. Such a rock uplift rate pattern is at odds with the horizontal velocity field, characterized by shortening and crustal thickening in the Eastern Alps and very limited deformation in the Central and Western Alps. Proposed mechanisms of rock uplift rate include isostatic response to the last deglaciation, long-term erosion, detachment of the Western Alpine slab, as well as lithospheric and surface deflection due to mantle convection. Here, we assess previous work and present new estimates of the contributions from these mechanisms. Given the large range of model estimates, the isostatic adjustment to deglaciation and erosion are sufficient to explain the full observed rate of uplift in the Eastern Alps, which, if correct, would preclude a contribution from horizontal shortening and crustal thickening. Alternatively, uplift is a partitioned response to a range of mechanisms. In the Central and Western Alps, the lithospheric adjustment to deglaciation and erosion likely accounts for roughly half of the rock uplift rate, which points to a noticeable contribution by mantle-related processes such as detachment of the European slab and/or asthenospheric upwelling. While it is difficult to independently constrain the patterns and magnitude of mantle contributions to ongoing Alpine vertical displacements at present, future data should provide additional insights. Regardless, interacting tectonic and surface mass redistribution processes, rather than an individual forcing, best explain ongoing Alpine elevation changes.
Published: 2019
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16. Réponse rapide au tremblement de terre Mw 4.9 du 11 novembre 2019 au Teil, dans la basse vallée du Rhône, en France

Author: Christophe Voisin, Michalis Foumelis, Léo Marconato, Emmanuelle Nayman, Martijn van den Ende, Florent Brenguier, Jérémy Billant, Marcello de Michele, Huihui Weng, Christophe Maron, Isabelle Douste-Bacque, Sébastien Hok, Raphaël Grandin, Axel Jung, Julie Régnier, Stéphane Guillot, A. Mordret, Romain Jolivet, Stéphane Baize, Matthieu Ferry, Fabrice Peix, Laurence Audin, Tiziano Giampietro, Jean-Paul Ampuero, Andrea Walpersdorf, Marianne Métois, Diane Rivet, Maxime Godano, Bérénice Froment, Michel Pernoud, Gauthier Guerin, Coralie Aubert, Antoine Schlupp, Martin Vallée, Valérie Sellier, Anne Socquet, Andy Combey, Emeline Maufroy, Catherine Pequegnat, Anne Deschamps, Antoine Mercier, Christian Sue, Marine Menager, Christophe Sira, Philippe Langlaude, Claudio Satriano, Olivier Cavalié, Diego Mercerat, Anne Paul, Estelle Hannouz, Céline Gélis, Philippe Vernant, Etienne Bertrand, Christophe Larroque, Pierre Briole, Chao Liang, Philippe Hervé Leloup, Rihab Sassi, Jean-François Ritz, Bertrand Delouis, Emmanuel Mathot, Mickael Langlais, Jérôme Chèze, David Wolynieck, Mathieu Causse, Ludmila Provost, Cécile Cornou, Marc Schaming, Xavier Martin, Rémi Dretzen, Itzhak Lior, Mohamed Chlieh, Elias el Haber, Elise Beck, Jean-Robert Grasso, Elif Oral, Benjamin Vial, Kevin Manchuel, Hervé Jomard, Pascal Allemand, Philippe Grandjean, Véronique Bertrand, Françoise Courboulex, Anthony Sladen, Didier Brunel, Aurélie Guilhem Trilla, Ildut Pondaven, Daniel Mata, Cécile Lasserre, Marc Grunberg, Alain Hernandez, Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut de Recherche pour le Développement (IRD), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), EDF (EDF), Terradue (ITALY), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ecole et Observatoire des Sciences de la Terre (EOST), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Pacte, Laboratoire de sciences sociales (PACTE), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Sciences Po Grenoble - Institut d'études politiques de Grenoble (IEPG ), Université Grenoble Alpes (UGA), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Grenoble Alpes (UGA)-Université Gustave Eiffel-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Laboratoire de géologie de l'ENS (LGE), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet MOUVGS (Cerema Equipe-projet MOUVGS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), UMS THETA (terre, homme, environnement, temps, astronomie) (UMS 3245) (OSU-THETA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Institut de Physique du Globe de Paris, École normale supérieure - Lyon (ENS Lyon), CEA DAM ILE-DE-FRANCE - Bruyères-le-Châtel [Arpajon] (CEA DAM IDF), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Terradue Srl, Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Sciences Po Grenoble - Institut d'études politiques de Grenoble (IEPG), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Laboratoire Chrono-environnement (UMR 6249) (LCE), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), PSE-ENV/SCAN/BERSSIN, ANR-15-CE31-0015,AlpArray-FR,Voir et comprendre les Alpes en 3D, de la croûte au manteau(2015), and ANR-11-EQPX-0040,RESIF-CORE,Réseau sismologique et géodésique français : l'équipement fondamental(2011)
Subjects: bepress|Physical Sciences and Mathematics, Earthquake, 010504 meteorology & atmospheric sciences, Magnitude (mathematics), bepress|Physical Sciences and Mathematics|Earth Sciences, Context (language use), Induced seismicity, Fault (geology), 010502 geochemistry & geophysics, InSAR interferometry, 01 natural sciences, bepress|Physical Sciences and Mathematics|Earth Sciences|Geophysics and Seismology, Le Teil Earthquake, Interferometric synthetic aperture radar, Surface rupture, Tremblement de terre, Le Teil, Rapid response, Aftershock, Seismology, Rhône valley, General Environmental Science, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, Le Teil earthquake, Rhône valley, Seismic sequence, Post-seismic, Surface rupture, InSAR interferometry, RESIF, seismic sequence, Massif, post-seismic, Tectonics, Sismologie, [SDU]Sciences of the Universe [physics], General Earth and Planetary Sciences, Geology, Séisme
Abstract: International audience; On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE–SW La Rouvière normal fault in reverse faulting in agreement with the present-day E–W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations), geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitor the temporal and spatial evolution of microearthquakes close to the fault plane and temporal evolution of the seismic response of 3 damaged historical buildings, and to study suspected site effects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by different institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakes along the major regional Cévenne fault system in a context of present-day compressional tectonics.
Published: 2020
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17. Active 650-km Long Fault System and Xolapa Sliver in Southern Mexico

Author: Krzysztof Gaidzik, Vladimir Kostoglodov, N. Cotte, A. Walpersdorf, María Teresa Ramírez-Herrera, Allen Husker, Ekaterina Kazachkina, and José Antonio Santiago
Subjects: geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Volcanic belt, GPS, oblique subduction, Terrain, sliver motion, Fault (geology), fault system, 010502 geochemistry & geophysics, 01 natural sciences, Tectonics, earthquake slip, Sinistral and dextral, Trench, General Earth and Planetary Sciences, tectonics, lcsh:Q, Shear zone, lcsh:Science, Forearc, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: New estimates of long-term velocities of permanent GPS stations in Southern Mexico reveal that the geologically discernible ∼650-km long shear zone, which strikes parallel to the Middle America trench, is active. This left-lateral strike-slip, La Venta–Chacalapa (LVC) fault system, is apparently associated with a motion of the Xolapa terrain and at the present time is the northern boundary of a ∼110–160-km wide forearc sliver with a sinistral motion of 3–6 mm/year with respect to the North America plate. This sliver is the major tectonic feature in the Guerrero and Oaxaca regions, which accommodates most of the oblique component of the convergence between the Cocos and North America plates. Previous studies based purely on the moment tensor coseismic slips exceedingly overestimated the sliver inland extent and allocated its northern margin on or to the north of the Trans-Mexican Volcanic Belt. While the LVC fault system probably slips slowly over geologic scale time and there is not any historic evidence of large earthquakes on the fault so far, its seismic potential could be very high, assuming a feasible order of ∼10³ years recurrence cycle. A detailed analysis of long-term position time series of permanent GPS stations in the Guerrero and Oaxaca states, Southern Mexico discards previous models and provides clear evidence of an active LVC fault zone bounding the Xolapa forearc sliver. The southeastward motion of this sliver may have persisted for the last ∼8–10 Million year and played an important role in the tectonic evolution of the region.
Published: 2020
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18. 3D surface velocity variations of the Argentière glacier (French Alps) monitored with a high resolution continuous GNSS network

Author: Mathilde Radiguet, Andrea Walpersdorf, Delphine Six, Stéphane Garambois, Jean-Noël Bouvier, Luc Piard, Jean-Louis Mugnier, Christian Sue, Martin Champon, Olivier Laarman, Laurent Ott, Benoit Urruty, Florent Gimbert, Agnès Helmstetter, Christian Vincent, Ugo Nanni, Stéphane Mercier, Luc Moreau, Olivier Romeyer, and Marguerite Mathey
Subjects: geography, geography.geographical_feature_category, GNSS applications, Resolution (electron density), Glacier, Surface velocity, Geodesy, Geology
Abstract: Five continuous GNSS stations monitor the Argentière glacier surface motion on a longitudinal profile at 2400 m altitude over a full melt season, from April to November 2019. High precision data analysis is enabled by a close-by reference station on the bedrock. This GNSS survey is part of the SAUSSURE project 2019-2022 that aims at increasing our knowledge on the physics of glacier basal sliding, by improving friction laws and validating them in a natural environment. The Argentière glacier is particularly interesting due to its long-term subglacial observatory measuring basal sliding velocity and subglacial discharge. The SAUSSURE project furthermore includes seismic, tiltmeter and piezometer measurements. The bedrock topography is obtained from a Ground Penetrating Radar.The dense GNSS station setup permits to validate individual antenna movements. We then retrieve horizontal and vertical surface velocities on daily and sub-daily time scales. We can deduce strain rates in between the stations and their evolution in time, and relate this observable with the vertical surface motions. The confrontation of the GNSS data with independent observations allows analyzing the surface motions searching for glacier surges that combine horizontal speed-ups combined with uplift due to bed separation of the ice sheet. These events could give indications about cavity growth in spring. We will also try to investigate sub-daily motions that seem to occur in daily cycles in summer, as hinted at by the basal sliding measurements. These daily cycles are usually also seen in the seismic activity. The phase of the different features varies with respect to the daily cycles of temperature and sub-glacial water pressure. These phase offsets can give us indices on eventual mechanisms of sliding at the bedrock interface. The GNSS measurements represent a rare in situ data set that can contribute to better apprehend mechanisms of basal sliding and to provide high-resolution 3D constraints on physical models of glacier flow.
Published: 2020
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19. 2017-2019 SSE sequence and its interaction with large earthquakes in Mexico

Author: Andrea Walpersdorf, Vladimir Kostoglodov, Mathilde Radiguet, Ekaterina Kazachkina, Jorge Jara, and Nathalie Cotte
Subjects: Large earthquakes, Geology, Seismology, Sequence (medicine)
Abstract: An intriguing sequence of a 2-stage SSE in Guerrero and a simultaneous SSE in Oaxaca took place in Mexico in 2017-2019. Three large earthquakes occur during these SSEs adding complexity to the observed surface deformations. The objective of this work is to explain the interaction between the overlapping seismic and aseismic events through the analysis of continuous GPS observations. We perform kinematic inversion of the GPS time series solving for the cumulative slip distribution on the subduction interface due to two SSEs, using Independent Component Analysis Inversion Method (ICAIM, Gualandi, 2015). The daily position time series for 2017-2019 are obtained by processing continuous data using GAMIT/GLOBK 10.7 (Herring et al, 2018). Strong postseismic signals generated by the following earthquakes 08/09/2017 Mw8.2 in Tehuantepec, 19/09/2017 Mw7.1 in Puebla-Morelos and 16/02/2018 Mw7.2 in Pinotepa are removed using the ICA decomposition. Our results show complex slip evolution on the subduction interface. We observe a clear change of cumulative seismic moment release rate after large seismic events of 2017 and after the earthquake in Pinotepa in 2018. The occurrence of Mw8.2 and Mw7.1 events notably slowed down the slip propagation of the Guerrero SSE. Continuous SSE in Oaxaca propagates from the northeast near the city of Oaxaca (-97.00°E, 16.70°N) towards the southwest approaching Pinotepa (-98.00°E, 17.00°N). Guerrero SSE migrates from the origin of its 1st phase near Tecpan (-100.50°E, 17.50°N) southeastwards to Acapulco (-99.50°E, 17.20°N) where the 2nd stage develops. Therefore the stress changes induced by the two aseismic events likely triggered the Mw7.2 Pinotepa earthquake (-98.01°E, 16.22°N).
Published: 2020
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20. Evidence of uplift at Argentière glacier (Mont Blanc area, France)

Author: Diego Cusicanqui, Fabien Gillet-Chaulet, Christian Vincent, Delphine Six, Luc Moreau, Adrien Gilbert, Bruno Jourdain, Andrea Walpersdorf, Olivier Laarman, Florent Gimbert, Olivier Gagliardini, and Luc Piard
Subjects: geography, geography.geographical_feature_category, Glacier, Physical geography, Mont blanc, Geology
Abstract: Understanding basal processes is a prerequisite for predicting the overall motion of glaciers and its response to climate change. Although a number of studies have shown that subglacial hydrology affects glacier’s basal sliding motion, the involved mechanisms remain poorly known. Several studies suggested that glacier velocity increases with englacial and subglacial water storage, but observational quantification of subglacial water storage and associated velocity changes are challenging to make due to uncertainties on velocity measurements and on vertical straining.Here we tackle this observational challenge through analyzing numerous field measurements from the surface and from the subglacial observatory on the Argentière Glacier (French Alps). We analyze specifically the relationships between daily sliding velocities (measured continuously at the glacier base), surface horizontal and vertical velocities from DGPS observations and ice thickness changes over years 2018 and 2019. We find strong upward surface movements of about 0.5 m during the winter until the beginning of May that cannot be explained by longitudinal strain rate changes. We support that it is caused by water volume increase in subglacial cavities.Further analyzing the relationships between cavity growth, sliding and surface velocities, we find that unlike in previous studies bed separation variations are not synchronous with sliding speed variations. Surface uplift starts in winter, which is long before the spring sliding acceleration, and surface drop occurs mid-summer, which is long before the end of summer sliding deceleration. These findings support that the link between subglacial water storage and sliding speed may not be as direct as previously thought.
Published: 2020
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21. Earthquake density along the Western Alpine Arc

Author: Andrea Walpersdorf, Margot Mathey, Stéphane Baize, Christian Sue, and Estelle Hannouz
Subjects: Arc (geometry), Geology, Seismology
Abstract: We propose a new analysis of the W-Alpine seismicity based on space and time distributions along the Alpine arc. The overall area bears witness of a relatively important seismic activity localized along the so-call Briançonnais and Piemontais seismic arcs, but also along alignments corresponding to individualized active fault, e.g. in front of the Belledonne massif, and locally in form of important seismic swarms (Ubaye, Maurienne, Mont-Blanc). The regional tectonic regime is well analyzed (see for instance Mathey et al., this session), with detailed mapping of both the stress and strain fields. However, actual available studies do not take into account the time and space distributions. Our study is developed using several available datasets covering various time spans and various strategies (local and regional seismic networks, template matching, historical seismic catalogue). We focus firstly on the space distribution of the activity along the arc, taking into account: (i) the simple occurrence of seismic events to calculate regional density maps, also investigating the B-value mapping; and (ii) the energy density, using the seismic moment fluxes per surface unit as a proxy. On this basis, we secondly analyze the time evolution of the seismicity, which is actually limited by the available dataset’s time span. Our integrated analyze focusses on 3 primary targets: (i) to compare the information arising from the different databases; (ii) to compare the most active zones in terms of earthquake occurrence vs. seismic energy released; (iii) to unravel potential evolutions or establish relative steadiness in alpine seismicity through time. This work will finally allow to better understand and discuss the Alpine seismicity’s mechanisms, in relation with the actual dynamics of this orogen.
Published: 2020
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22. Geomorphology of the cumulative deformation since Oligocene age on the Mw 4.9 Le Teil earthquake fault (South of France,11/11/19)

Author: Matthieu Ferry, Laurence Audin, Christophe Larroque, Andy Combey, Jean-François Ritz, Christian Sue, Stéphane Baize, Anne Lemoine, Estelle Hannouz, and Andrea Walpersdorf
Subjects: Deformation (meteorology), Geomorphology, Geology
Abstract: The Mw 4.9 earthquake that occurred near Montelimar on November 11, 2019 showed peculiar characteristics: a very shallow hypocenter (1km depth) with unexpected surface ruptures for such a moderate magnitude, and only few aftershocks showing low magnitudes (ML < 2.7). This event occurred in the industrialized Rhone Valley (including nuclear power plants and chemical industry) where several historical earthquakes with similar intensities and magnitudes took place (e.g. 1773, 1873, 1934).The earthquake broke a ~5-km-long segment of the northern tip of the Cevennes fault system (La Rouvière Fault Segment). This ~100 km-long fault network has a NE-SW orientation trend and is inherited from the Variscan orogeny (~300 Ma). It first registered an extensive and transtensive tectonic phase ending at the Oligocene age (~30 Ma) before being inverted, as revealed by the reverse focal mechanism of the Le Teil event.To date, this fault network has been poorly investigated in terms of seismic hazard, likely due to the low Mw expected on such short structures. Therefore, we started a new study to document its paleo-earthquake record in the framework of the new French RGF program (Alps and surrounding basins, BRGM).Our first target was to map the cumulative trace of the fault. A first airborne LiDAR survey was acquired by helicopter and UAV (unmanned aerial vehicle) just after the earthquake. They allowed the identification of a continuous inherited scarp of 1 – 2 m in height over ~4 km along the preexisting Oligocene fault. In order characterize the post-Oligocene deformation along this fault, we performed a detailed analysis of geomorphological field observations, as well as a geophysical study by acquisition of seismic, electrical and ground-penetrating radar profiles. These profiles aimed to better understand how the 11/11/19 earthquake surface rupture is connected at depth to the Oligocene structure (La Rouvière Fault).Each step of the analysis aims at eventually locating sites for further paleoseismological trenches, accounting for fault location, sediment preservation with favorable age determination potential and accessibility. This kind of investigation will provide information on the evolution over time of the seismic activity of this fault network, as well as relevant data on the current hazard they present in the specific context of the French Rhone Valley.
Published: 2020
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23. How to reveal the present-day mechanism of the 600 km long Doruneh fault in eastern Iran ?

Author: Hamid Reza Nankali, Y. Djamour, Reza Sa'adat, Andrea Walpersdorf, Marie-Pierre Doin, Zahra Mousavi, Erwan Pathier, Richard Walker, F. Tavakoli, and Fateme Khorrami
Subjects: geography, geography.geographical_feature_category, Present day, Fault (geology), Mechanism (sociology), Geology, Seismology
Abstract: The enigmatic 600 km long E-W trending left-lateral Doruneh fault in eastern Iran is certified to be active by its well preserved geomorphological features all along its trace, but it is lacking recent seismic activity that could be attributed to its motion. Instead, the high seismogenic potential of the study zone is highlighted by the two M=7 earthquakes on the left-lateral E-W trending Dasht-e-Bayaz fault just south of Doruneh, in 1968 and 1979. Therefore, it remains important to understand the role of the Doruneh fault in the kinematics of the Arabia-Eurasia collision that takes place inside Iran’s political boundaries.Many different slip-rates have been estimated for the left-lateral motion of the Doruneh fault: 2.5 mm/yr by geomorphological marker offset dating, 1 mm/yr from preliminary GNSS measurements, and 5 mm/yr from a local InSAR study. These rather local estimates on the 600 km long fault highlight either temporal or spatial variability of the Doruneh present-day behavior. The spatial variability of the fault slip is still badly constraint as the western half of the fault is located in the Great Kavir desert. The analysis of satellite radar images was supposed to provide good constraints on the inter-seismic deformation with a full spatial coverage of the fault, especially thanks to the favorable E-W orientation of the Doruneh fault and the arid Iranian climate. However, decorrelation due to sand dunes and unexpected large tropospheric noise prohibited precise results from a first large-scale ENVISAT study, yielding an upper limit of the slip rate of 4 mm/yr. The high resolution SENTINEL-1 constellation (operational since 2014) is predicted to provide constraints on inter-seismic velocities down to 2 mm/yr from 2020 on. In complement, a dense GNSS survey has been conducted in 2012 and 2018 on a temporary network of 18 sites around a large part of the fault. This network densifies and completes the 17 permanent GNSS stations in up to 200 km distance to the fault trace situated mostly in the eastern, more populated part of the fault.In this work, we will point out our recent GNSS, InSAR and tectonic studies on the present-day characteristics of the Doruneh fault, to better understand the mechanism of this major fault in the kinematics of the Arabia-Eurasia collision, and to contribute to a better assessment of the seismic hazard in eastern Iran.
Published: 2020
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24. Independent Component Analysis and Parametric Approach for Source Separation in InSAR Time Series at Regional Scale: Application to the 2017–2018 Slow Slip Event in Guerrero (Mexico)

Author: Marie-Pierre Doin, Vladimir Kostoglodov, Andrea Walpersdorf, Mathilde Radiguet, Simon Daout, Erwan Pathier, L. Maubant, Ekatarina Kazachkina, Nathalie Cotte, Institut des Sciences de la Terre (ISTerre), and Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Slip (materials science), 010502 geochemistry & geophysics, Geodesy, 01 natural sciences, Independent component analysis, Geophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Interferometric synthetic aperture radar, Earth and Planetary Sciences (miscellaneous), Source separation, Geology, 0105 earth and related environmental sciences, Parametric statistics
Abstract: International audience; Separating different sources of signal in Interferometric Synthetic Aperture Radar (InSAR) studies over large areas is challenging, especially between the long‐wavelength changes of atmospheric conditions and tectonic deformations, both correlated to elevation. In this study, we focus on the 2017–2018 slow slip event (SSE) in the Guerrero state (Mexico) where (1) the permanent GPS network has a low spatial density (less than 30 stations in an area of 300 urn:x-wiley:jgrb:media:jgrb54081:jgrb54081-math-0001 300 km) with uneven distribution; (2) the tropospheric phase delays can be as high as 20 cm of apparent ground displacements, with a complex temporal evolution; (3) the tested global weather models fail to correct interferograms with enough accuracy (with residual tropospheric signal higher than the tectonic signal); and (4) the surface displacement caused by the seismic cycle shows complex interactions between seismic sequences and aseismic events. To extract the SSE signal from Sentinel‐1 InSAR time series, we test two different approaches. The first (parametric method) consists of a least squares linear inversion, imposing a functional form for each deformation or atmospheric component. The second uses independent component analysis of the InSAR time series. We obtain time series maps of surface displacements along the radar line of sight associated with the SSE and validate these results with a comparison to GPS. Combining those two approaches, we propose a method to separate atmospheric delays and tectonic deformation on time series data not corrected from atmospheric delays. From the extracted ground deformation maps, we propose a first‐order slip inversion model at the subduction interface during this SSE.
Published: 2020
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25. An 8 month slow slip event triggers progressive nucleation of the 2014 Chile megathrust

Author: Fabrice Cotton, Edmundo Norabuena, Daniel Carrizo, Jorge Jara, Andrea Walpersdorf, Anne Socquet, Nathalie Cotte, Sebastian Specht, Francisco Ortega-Culaciati, and Jesus Piña Valdes
Subjects: Geophysics, 010504 meteorology & atmospheric sciences, General Earth and Planetary Sciences, Episodic tremor and slip, Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: LabeX OSUG SMINGUE IRD AO-Sud INSU-Aleas grants CONICYT through "Becas Chile" PhD fellowships Proyecto Fondecyt 11140904 PNTS-2014-08
Published: 2017
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26. An up-to-date crustal deformation map of Iran using integrated campaign-mode and permanent GPS velocities

Author: Parastoo Tavakoli, Seyed Abdolreza Saadat, Fatemeh Khorrami, Mahnaz Alijanzade, H. Nankali, Philippe Vernant, Zahra Mousavi, Sedighe Hosseini, Frédéric Masson, Azade Aghamohammadi, Andrea Walpersdorf, Faramarz Nilfouroushan, National Cartographic Center [Iran] (NCC), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute for Advanced Studies in Basic Sciences (IASBS), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), and Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)
Subjects: Asia, Satellite geodesy, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Kinematics, 010502 geochemistry & geophysics, 01 natural sciences, Geochemistry and Petrology, and high strain zone, 0105 earth and related environmental sciences, Shore, geography, geography.geographical_feature_category, Subduction, business.industry, Geodetic datum, faults, satellite Geodesy, Geodesy, Geophysics, Fracture, Coupling (computer programming), GNSS applications, Global Positioning System, subduction zone processes, business, Geology
Abstract: International audience; We present the most extensive and up-to-date unified GPS velocity field for Iran. We processed the data collected during 10 yr (2006–2015) from the Iranian Permanent GNSS Network (IPGN) and combined them with previously published velocity solutions from the GPS survey measurements during 1997–2013. We analysed this velocity field using a continuum approach to compute a new strain-rate map for this region and we designed a block model based on the main geological, morphological and seismic structures. Comparison between both approaches suggests similar results and allows us to present the first comprehensive first-order fault-slip-rate estimates for the whole of Iran. Our results confirm most of the results from previous geodetic studies. However, we also show a trade-off between the coupling ratio of the Iranian Makran subduction interface and the kinematics of the faults north of the Makran in the Jazmurian depression. Indeed, although too scarce to accurately estimate a coupling ratio, we show that coupling higher than 0.4 on the plate interface down to a depth of 25 km will induce extension on the E–W faults in the Jazmurian region. However, the sites close to the shoreline suggest a low coupling ratio; hence, the coupling on this plate interface is probably more complicated than previously described and the Iranian Makran subduction interface mechanical behaviour might be similar to that on the Hellenic subduction zone.
Published: 2019
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27. The 2006 Collapse of the Bérard Rock Glacier (Southern French Alps)

Author: Xavier Bodin, Jean-Michel Krysiecki, Lionel Lorier, Thomas Echelard, Philippe Schoeneich, Michel Peyron, Olivier Le Roux, and A. Walpersdorf
Subjects: Glacier ice accumulation, 010504 meteorology & atmospheric sciences, Tidewater glacier cycle, Rock glacier, 15. Life on land, Cirque glacier, 010502 geochemistry & geophysics, Permafrost, Fault scarp, 01 natural sciences, Randkluft, Glacier mass balance, 13. Climate action, Geomorphology, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: In the Mediterranean French Alps, the Berard rock glacier suddenly collapsed during the summer of 2006; this was a rarely documented event in the world, exceptional for the amount of disturbed material (estimated at 250 000–500 000 m3). Located near the lower limit of permafrost, the Berard rock glacier collapse might exemplify the possible consequences of the degradation of ice-rich mountain permafrost. The causes of the collapse may include long-term atmospheric warming, recent air temperature anomalies, niveo-meteorological conditions prior to the collapse, geological settings and topographical context. Geomorphological interpretations and analysis of climatic data-sets allow us to specify the different stages of the collapse and discuss the respective roles of the geological and hydro-climatic factors and unfrozen water in the ground which could have led to the collapse. Geophysical measurements and ice observations in the scarp reveal that the internal structure of the intact part of the rock glacier is composed of both ice-cemented and massive-ice layers. The rock glacier also contains a high proportion of fine material (essentially silt and clay), which could have played an important role in the collapse. Geodetic measurements repeated since 2007 show that, with the exception of the upper part, the whole rock glacier was still experiencing destabilisation in 2010, with very high deformation rates exceeding 30 m in 3 years. The continuous monitoring of surface displacement carried out during the summer of 2007 has not shown any clear meteorological control on the post-collapse rock glacier dynamics. Copyright © 2016 John Wiley & Sons, Ltd.
Published: 2016
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28. Corrigendum to 'Kinematic study of Iquique 2014 M 8.1 earthquake: Understanding the segmentation of the seismogenic zone' [Earth Planet. Sci. Lett. 503 (2018) 131–143]

Author: John Díaz-Mojica, Edmundo Norabuena, Jean Virieux, Andrea Walpersdorf, Andrei Maksymowicz, Javier Ruiz, Jorge Jara, Hugo Sánchez-Reyes, Fabrice Cotton, Anne Socquet, and Nathalie Cotte
Subjects: Geophysics, Space and Planetary Science, Geochemistry and Petrology, Planet, Earth and Planetary Sciences (miscellaneous), Segmentation, Kinematics, Geology, Earth (classical element)
Published: 2019

29. Slow Slip History for the MEXICO Subduction Zone: 2005 Through 2011

Author: S. E. Graham, B. Rousset, Vladimir Kostoglodov, A. Walpersdorf, Robert McCaffrey, Cécile Lasserre, Enrique Cabral-Cano, Luis Salazar-Tlaczani, Charles DeMets, and Nathalie Cotte
Subjects: Seismic gap, 010504 meteorology & atmospheric sciences, Subduction, Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Geochemistry and Petrology, Earthquake cycle, Gps data, Coulomb failure stress, Episodic tremor and slip, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: To further our understanding of the seismically hazardous Mexico subduction zone, we estimate the first time-dependent slip distributions and Coulomb failure stress changes for the six major slow slip events (SSEs) that occurred below Mexico between late 2005 and mid-2011. Slip dist ributions are the first to be estimated from all continuous GPS data in central and southern Mexico, which better resolves slow slip in space and time than was previously possible in this region. Below Oaxaca, slip during previously un-modeled SSEs in 2008/9 and 2010/11 extended farther to the west than previous SSEs. This constitutes the first evidence that slow slip accounts for deep slip within a previously noted gap between the Oaxaca and Guerrero SSE source regions. The slip that we estimate for the two SSEs that originated below Guerrero between 2005 and 2011 agrees with slip estimated in previous, mostly static-offset SSE modeling studies; however, we show that both SSEs migrated eastward toward the Oaxaca SSE source region. In accord with previous work, we find that slow slip below Guerrero intrudes up-dip into the potentially seismogenic region, presumably accounting for some of the missing slip within the well-described Guerrero seismic gap. In contrast, slow slip below Oaxaca between 2005 and 2011 occurred mostly down-dip from the seismogenic regions defined by the rupture zones of large thrust earthquakes in 1968 and 1978 and released all of the slip deficit that accumulated in the down-dip region during this period.
Published: 2015
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30. Present-Day Deformations of the Jura Arc Inferred by GPS Surveying and Earthquake Focal Mechanisms

Author: Julie Albaric, Andrea Walpersdorf, Benjamin Fores, Pierre Sakic, Christian Sue, Mickael Rabin, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), GFZ, GPS-JURA, Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), and GeoForschungsZentrum - Helmholtz-Zentrum Potsdam (GFZ)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, business.industry, Infinitesimal strain theory, Present day, Deformation (meteorology), 010502 geochemistry & geophysics, 01 natural sciences, Data set, Coupled sismotectonic-geodesic study of the Jura arc (northwestern most part of the Alps)Decoupling between basement and sedimentary cover in the northeastern partGood coherency between GPS and seismotectonics results, Geophysics, Basement (geology), Geochemistry and Petrology, Global Positioning System, Sedimentary rock, business, Foreland basin, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: International audience; This study presents a compilation of more than 40 years of seismotectonic data, including 54 computed focal mechanisms, combined with 15 years of GPS data coming from a dense network of 35 permanent GPS stations within the Jura arc and its vicinity. These data are compared to previous available geomorphological, geophysical, and structural studies in order to discuss the 3D distribution of the deformation within the Jura arc. GPS data show coherent schemes in terms of velocities and allowed to discriminate between two provinces (NE of the belt and in its front/foreland). They also constrain a low but significant overall strain tensor with a NNW-SSE shortening of 2.16 nanostrain/year associated with an ENE-WSW extension of 0.44 nanostrain/year. The seismotectonic approach is based on a data set of 2,400 events and 54 focal mechanisms. Inversions of the focal mechanisms both globally and in homogeneous sectors highlight a general strike-slip deformation regime, with sigma1 oriented NW-SE and sigma3 oriented NE-SW. We discriminate two different sectors in terms of basement/cover (un)coupling: (1) potentially decoupled deformation between the basement and the sedimentary cover in the NE part; and (2) coupled deformation in the sedimentary cover and its basement in the Jura foreland.
Published: 2018
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31. Kinematic study of Iquique 2014 M 8.1 earthquake: Understanding the segmentation of the seismogenic zone

Author: Fabrice Cotton, Nathalie Cotte, Jean Virieux, Jorge Jara, Andrea Walpersdorf, Anne Socquet, Andrei Maksymowicz, Edmundo Norabuena, John Díaz-Mojica, Hugo Sánchez-Reyes, and J. A. Ruiz
Subjects: Seismic gap, 010504 meteorology & atmospheric sciences, Subduction, Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Amplitude, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Seismic moment, Bathymetry, Gravimetry, Aftershock, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: We study the rupture processes of Iquique earthquake M w 8.1 (2014/04/01) and its largest aftershock M w 7.7 (2014/04/03) that ruptured the North Chile subduction zone. High-rate Global Positioning System (GPS) recordings and strong motion data are used to reconstruct the evolution of the slip amplitude, rise time and rupture time of both earthquakes. A two-step inversion scheme is assumed, by first building prior models for both earthquakes from the inversion of the estimated static displacements and then, kinematic inversions in the frequency domain are carried out taken into account this prior information. The preferred model for the mainshock exhibits a seismic moment of 1.73 × 1021 Nm ( M w 8.1) and maximum slip of ∼9 m, while the aftershock model has a seismic moment of 3.88 × 1020 ( M w 7.7) and a maximum slip of ∼3 m. For both earthquakes, the final slip distributions show two asperities (a shallow one and a deep one) separated by an area with significant slip deficit. This suggests a segmentation along-dip which might be related to a change of the dipping angle of the subducting slab inferred from gravimetric data. Along-strike, the areas where the seismic ruptures stopped seem to be well correlated with geological features observed from geophysical information (high-resolution bathymetry, gravimetry and coupling maps) that are representative of the long-term segmentation of the subduction margin. Considering the spatially limited portions that were broken by these two earthquakes, our results support the idea that the seismic gap is not filled yet.
Published: 2018

32. GPS constraints on the Mw = 7.5 Ometepec earthquake sequence, southern Mexico: coseismic and post-seismic deformation

Author: S. E. Graham, Michael R. Brudzinski, Vladimir Kostoglodov, A. Walpersdorf, Enrique Cabral-Cano, Robert McCaffrey, Charles DeMets, Nathalie Cotte, and Luis Salazar-Tlaczani
Subjects: Sequence (geology), Geophysics, Transient deformation, Geochemistry and Petrology, business.industry, Global Positioning System, Deformation (meteorology), business, Geodesy, Seismic cycle, Geology, Seismology
Published: 2014
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33. GPS constraints on the 2011-2012 Oaxaca slow slip event that preceded the 2012 March 20 Ometepec earthquake, southern Mexico

Author: Enrique Cabral-Cano, Charles DeMets, Michael R. Brudzinski, Nathalie Cotte, S. E. Graham, Vladimir Kostoglodov, A. Walpersdorf, Luis Salazar-Tlaczani, and Robert McCaffrey
Subjects: Geophysics, Transient deformation, Geochemistry and Petrology, business.industry, Global Positioning System, Slip (materials science), business, Seismic cycle, Seismology, Geology
Published: 2014
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34. Present-day kinematics and fault slip rates in eastern Iran, derived from 11 years of GPS data

Author: A. Aghamohammadi, Mathilde Vergnolle, M. Sedighi, Y. Djamour, H. Nankali, Zahra Mousavi, Denis Hatzfeld, Aurelien Bigot, A. Jadidi, F. Tavakoli, Isabelle Manighetti, and Andrea Walpersdorf
Subjects: 010504 meteorology & atmospheric sciences, business.industry, Crust, Slip (materials science), Induced seismicity, Present day, 010502 geochemistry & geophysics, Horizontal plane, Collision zone, 01 natural sciences, Geophysics, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Global Positioning System, Clockwise, business, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: We analyze new GPS data spanning 11 years at 92 stations in eastern Iran. We use these data to analyze the present-day kinematics and the slip rates on most seismogenic faults in eastern Iran. The east Lut, west Lut, Kuhbanan, Anar, Dehshir, and Doruneh faults are confirmed as the major faults and are found to currently slip laterally at 5.6 ± 0.6, 4.4 ± 0.4, 3.6 ± 1.3, 2.0 ± 0.7, 1.4 ± 0.9, and 1.3 ± 0.8 mm/yr, respectively. Slip is right-lateral on the ~NS striking east Lut, west Lut, Kuhbanan, Anar, and Dehshir faults and left-lateral on the ~EW Doruneh fault. The ~NS faults slice the eastern Iranian crust into five blocks that are moving northward at 6–13 mm/yr with respect to the stable Afghan crust at the eastern edge of the collision zone. The collective behavior of the ~NS faults might thus allow the Arabian promontory to impinge northward into the Eurasian crust. The ~NS faults achieve additional NS shortening by rotating counterclockwise in the horizontal plane, at current rates up to 0.8°/Ma. Modeling the GPS and available geological data with a block rotation model suggests that the rotations have been going on at a similar rate (1 ± 0.4°/Ma) over the last 12 Ma. We identify large strains at the tips of the rotating east Lut, west Lut, and Kuhbanan faults, which we suspect to be responsible for the important historical and instrumental seismicity in those zones.
Published: 2014
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35. Seismic velocity changes, strain rate and non-volcanic tremors during the 2009–2010 slow slip event in Guerrero, Mexico

Author: Mathilde Radiguet, Nikolai M. Shapiro, Diane Rivet, Víctor M. Cruz-Atienza, Michel Campillo, Vladimir Kostoglodov, Dimitri Zigone, Glenn Cougoulat, Andrea Walpersdorf, Eric G. Daub, Nathalie Cotte, Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Instituto de Geofisica [Mexico], Universidad Nacional Autónoma de México (UNAM), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Instituto de Geofísica, Agence National de la Recherche (France) under the contract RA0000CO69 ‘G-GAP’, by the European Research Council Advanced Grant 227507 «Whisper» and byproject grants form CONACYT 84544 and PAPIIT IN110611 andIN103808, Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Seismometer, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Ambient noise level, Crust, Slip (materials science), Strain rate, Seismic noise, 010502 geochemistry & geophysics, Geodesy, 01 natural sciences, Geophysics, Volcano, Rheology and friction of fault zones, Geochemistry and Petrology, Wave scattering and diffraction, Seismic array, Subduction zone processes, sense organs, skin and connective tissue diseases, Seismology, Geology, 0105 earth and related environmental sciences
Abstract: International audience; Seismic velocity changes, strain rate and non-volcanic tremors during the S U M M A R Y We use ambient noise cross-correlations to monitor small but reliable changes in seismic velocities and to analyse non-volcanic tremor (NVT) intensities during the slow slip event (SSE) that occurred in 2009 and 2010 in Guerrero. We test the sensitivity of the seismic velocity to strain variations in absence of strong motions. The 2009-2010 SSE presents a complex slip sequence with two subevents occurring in two different portions of the fault. From a seismic array of 59 seismometers, installed in small antennas, we detect a velocity drop with maximum amplitude at the time of the first subevent. We analyse the velocity change at different period bands and observe that the velocity perturbation associated with the SSE maximizes for periods longer than 12 s. Then a linearized inversion of the velocity change measured at different period bands is applied in order to determine the depth of the portion of the crust affected by this perturbation. No velocity change in the first 10 km is detected. Below, the velocity perturbation increases with depth, affecting the middle and lower crust. Finally, we compute the transient deformation produced by the SSE in an elastic model using the slip evolution recovered from the inversion of continuous GPS. The comparison between the velocity changes and the deformation suggests that the velocity change is correlated with the strain rate rather than with the strain. This result is similar to what was observed during the 2006 SSE in the same region and suggests a non-linear behaviour of the crust. The velocity changes can be interpreted together with other observables such as NVTs. During the 2009-2010 SSE we measure NVT activity using continuous seismic records filtered between 2 and 8 Hz. We observe a correlation between velocity changes (for period band greater than 14 s) and tremor activity whereas no correlation exists between velocity changes and seismic noise energy measured at long periods. These observations suggest that both seismic velocity change and NVT can be used as indication of transient deformation at depth.
Published: 2013
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36. Global Positioning System constraints on the active tectonics of NE Iran and the South Caspian region

Author: Y. Djamour, H. Nankali, Andrea Walpersdorf, F. Tavakoli, Richard Walker, Faramarz Nilfouroushan, Zahra Mousavi, and Erwan Pathier
Subjects: geography, geography.geographical_feature_category, business.industry, Slip (materials science), Fault (geology), Structural basin, Geodesy, Euler's rotation theorem, symbols.namesake, Tectonics, Geophysics, Seismic hazard, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Global Positioning System, symbols, business, Longitude, Geology, Seismology
Abstract: Article history: We present a velocity field compiled from a network of 27 permanent and 20 campaign GPS stations across NE Iran. This new GPS velocity field helps to investigate how Arabia-Eurasia collision deformation is accommodated at the northern boundary of the deforming zone. The present-day northward motion decreases eastward from 11 mm/yr at Tehran (∼52 ◦ E) to 1.5 mm/yr at Mashhad (∼60 ◦ E). N-S shortening across the Kopeh Dagh, Binalud and Koh-e-Sorkh ranges sums to 4.5 ± 0. 5m m /yr at longitude 59 ◦ E. The available GPS velocities allow us to describe the rigid-body rotation of the South Caspian about an Euler pole that is located further away than previously thought. We suggest that two new stations (MAVT and MAR2), which are sited far from the block boundaries, are most likely to indicate the full motion of the South Caspian basin. These stations suggest that NW motion is accommodated by right-lateral slip on the Ashkabad fault (at a rate of up to 7 mm/yr) and by up to 4-6 mm/yr of summed left- lateral slip across the Shahroud left-lateral strike-slip system. Our new GPS results are important for assessing seismic hazard in NE Iran, which contains numerous large population centers and possesses an abundant historical earthquake record. Our results suggest that the fault zones along the eastern Alborz and western Kopeh Dagh may accommodate slip at much faster rates than previously thought. Fully assessing the role of these faults, and the hazard that they represent, requires independent verification of their slip-rates through additional GPS measurements and geological fieldwork.
Published: 2013
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37. Slow slip event in the Mexican subduction zone: Evidence of shallower slip in the Guerrero seismic gap for the 2006 event revealed by the joint inversion of InSAR and GPS data

Author: Mathilde Radiguet, Mathilde Vergnolle, A. Walpersdorf, Nathalie Cotte, Vladimir Kostoglodov, Fabrice Cotton, Olivier Cavalié, Erwan Pathier, Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Instituto de Geofisica [Mexico], Universidad Nacional Autónoma de México (UNAM), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), and Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM)
Subjects: Seismic gap, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, slow slip event, InSAR, Geochemistry and Petrology, Interferometric synthetic aperture radar, Earth and Planetary Sciences (miscellaneous), Slipping, 0105 earth and related environmental sciences, seismic cycle, Subduction, business.industry, Geodesy, Geophysics, Space and Planetary Science, Trench, subduction zone processes, Global Positioning System, Episodic tremor and slip, business, Geology, Seismology
Abstract: Slow slip events (SSEs) in subduction zones have been observed in the last decade with continuous GPS stations. Some of them could be related to the lateral segmentation of subduction interface that seems to be a critical parameter for the propagation of large subduction earthquakes. In 2006, one of the largest SSEs recorded so far was captured by a dozen continuous GPS stations, in the Guerrero area (Mexico) along the Mexican subduction zone. Previous studies based on these data suggested a lateral variation of the updip depth of the SEE at the Guerrero seismic gap, but suffered from a lack of resolution east of the gap. Here, we show the ability of InSAR technique to capture a part of the 2006 SSE cumulative displacement east of the Guerrero gap by a stacking approach. We processed long strip Envisat interferograms corrected for orbital errors and interseismic signal using GPS data. We first use a forward modelling approach to test InSAR sensitivity to the amount of slip, depth and width of the slipping area on the subduction interface. Due to its high spatial resolution, InSAR allows one to comprehensively sample the North-South spatial wavelength of the SSE deformation, complementing the sparse GPS network. InSAR locates the maximum of uplift and subsidence caused by the SSE more precisely than the GPS data, giving better constraints on the updip slip limit of the SSE. We then inverted the InSAR and GPS data separately to understand how each inversion resolves the slip at depth. Finally, we performed a joint inversion of InSAR and GPS data, which constrained the SSE slip and its location on the plate interface over the entire Guerrero area. The joint inversion shows significant lateral variation of the SSE slip distribution along the trench with a shallower updip edge in the Guerrero seismic gap, west of Acapulco, and a deeper slip edge further east. (C) 2013 Elsevier B.V. All rights reserved.
Published: 2013
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38. Is the Okavango Delta the terminus of the East African Rift System? Towards a new geodynamic model: geodetic study and geophysical review

Author: Kaelo Makati, Mike Murray-Hudson, Olivier Dauteuil, Frédérique Moreau, Anne-Morwenn Pastier, A. Walpersdorf, Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Okavango Research Institute, University of Botswana, Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique, Université de Rennes 1, Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, Rift, 010504 meteorology & atmospheric sciences, Intraplate tectonics, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Crust, Geophysics, East African Rift System, 010502 geochemistry & geophysics, 01 natural sciences, Graben, Tectonics, Craton, Lithosphere, Okavango, East African Rift, Bouguer anomaly, Seismology, Geology, Geodesy, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: International audience; The Okavango Graben (OG) has been considered as the terminus of the southwestern branch of the East African Rift System (EARS) since the 1970's based on fault morphology and early seismic and geophysical data. Thus it is assumed to be an incipient rifting zone, analogous to the early stage of mature rifts in the EARS. Recent geodetic data and geophysical studies in the area bring new insights on the local crust and lithosphere, mantle activity and fault activity. In this study, we computed the velocities for three permanent GPS stations surrounding the graben and undertook a review of the new geophysical data available for the area. The northern and southern blocks of the graben show exclusively a low strike-slip displacement rate of about 1 mm/yr, revealing the transtensional nature of this basin. The seismic record of central and southern Africa is revealed to be instrumentally biased for the events recorded before 2004 and the OG may not represent the most seismically active area in Botswana anymore. Moreover, no significant lithosphere and crustal thinning is found in the tectonic structure as well as no strong negative Bouguer anomaly and surface heat flux. Thus the OG does not match the classical model for a rifting zone. We propose a new geodynamic model for the deformation observed west of the EARS based on accommodation of far-field deformation due to the differential extension rates of the EARS and the displacement of the Kalahari craton relative to the Nubian plate.
Published: 2017
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39. Triggering of the 2014 M_w7.3 Papanoa earthquake by a slow slip event in Guerrero, Mexico

Author: Adriano Gualandi, T. Lhomme, E Cabral Cano, Vladimir Kostoglodov, Nathalie Cotte, Mathilde Radiguet, Bernard Valette, Michel Campillo, A. Walpersdorf, and Hugo Perfettini
Subjects: 010504 meteorology & atmospheric sciences, Subduction, Slip (materials science), Geodynamics, 010502 geochemistry & geophysics, 01 natural sciences, Slow earthquake, Gps network, Static stress, General Earth and Planetary Sciences, Aseismic slip, Episodic tremor and slip, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: Since their discovery two decades ago(1,2), slow slip events have been shown to play an important role in accommodating strain in subduction zones. However, the physical mechanisms that generate slow slip and the relationships with earthquakes are unclear. Slow slip events have been recorded in the Guerrero segment of the Cocos-North America subduction zone(2,3). Here we use inversion of position time series recorded by a continuous GPS network to reconstruct the evolution of aseismic slip on the subduction interface of the Guerrero segment. We find that a slow slip event began in February 2014, two months before the magnitude (M-w) 7.3 Papanoa earthquake on 18 April. The slow slip event initiated in a region adjacent to the earthquake hypocentre and extended into the vicinity of the seismogenic zone. This spatio-temporal proximity strongly suggests that the Papanoa earthquake was triggered by the ongoing slow slip event. We demonstrate that the triggering mechanism could be either static stress increases in the hypocentral region, as revealed by Coulomb stress modelling, or enhanced weakening of the earthquake hypocentral area by the slow slip. We also show that the plate interface in the Guerrero area is highly coupled between slow slip events, and that most of the accumulated strain is released aseismically during the slow slip episodes.
Published: 2016

40. Present-day uplift of the western Alps

Author: Nocquet, J. -m., Sue, Christian, Walpersdorf, A., Tran, T., Lenotre, N., Lenôtre, Nicole, VERNANT, Philippe, Cushing, M., Jouanne, F., Masson, Frédéric, Baize, S., CHERY, Jean, Van der beek, P. a., Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Institut de physique du globe de Strasbourg (IPGS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Laboratoire Chrono-environnement (UMR 6249) (LCE), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géoazur ( GEOAZUR ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Université de Franche-Comté ( UFC ) -Centre National de la Recherche Scientifique ( CNRS ), Institut des Sciences de la Terre ( ISTerre ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux ( IFSTTAR ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Bureau de Recherches Géologiques et Minières (BRGM) ( BRGM ), Université des Antilles et de la Guyane ( UAG ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université de Montpellier ( UM ) -Centre National de la Recherche Scientifique ( CNRS ), Risques ( Géosciences Montpellier ), Université des Antilles et de la Guyane ( UAG ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université de Montpellier ( UM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université des Antilles et de la Guyane ( UAG ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université de Montpellier ( UM ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Radioprotection et de Sûreté Nucléaire ( IRSN ), Institut de physique du globe de Strasbourg ( IPGS ), and Université de Strasbourg ( UNISTRA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS )
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Multidisciplinary, 010504 meteorology & atmospheric sciences, Levelling, [SDE.MCG]Environmental Sciences/Global Changes, western alps, [ SDU.STU.TE ] Sciences of the Universe [physics]/Earth Sciences/Tectonics, Post-glacial rebound, Present day, 010502 geochemistry & geophysics, Geodesy, 01 natural sciences, Article, [ SDE.MCG ] Environmental Sciences/Global Changes, Tectonics, Gps data, Gravitational collapse, Erosion, Glacial period, Geology, 0105 earth and related environmental sciences
Abstract: Collisional mountain belts grow as a consequence of continental plate convergence and eventually disappear under the combined effects of gravitational collapse and erosion. Using a decade of GPS data, we show that the western Alps are currently characterized by zero horizontal velocity boundary conditions, offering the opportunity to investigate orogen evolution at the time of cessation of plate convergence. We find no significant horizontal motion within the belt, but GPS and levelling measurements independently show a regional pattern of uplift reaching ~2.5 mm/yr in the northwestern Alps. Unless a low viscosity crustal root under the northwestern Alps locally enhances the vertical response to surface unloading, the summed effects of isostatic responses to erosion and glaciation explain at most 60% of the observed uplift rates. Rock-uplift rates corrected from transient glacial isostatic adjustment contributions likely exceed erosion rates in the northwestern Alps. In the absence of active convergence, the observed surface uplift must result from deep-seated processes.
Published: 2016
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41. A geodetic matched filter search for slow slip with application to the Mexico subduction zone

Author: Vladimir Kostoglodov, Andrea Walpersdorf, B. Rousset, Michel Campillo, Cécile Lasserre, William B. Frank, Nathalie Cotte, and Anne Socquet
Subjects: 010504 meteorology & atmospheric sciences, Subduction, Matched filter, Geodetic datum, Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Episodic tremor and slip, Geology, Seismology, 0105 earth and related environmental sciences
Published: 2017
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42. Monitoring Temperate Glacier Displacement by Multi-Temporal TerraSAR-X Images and Continuous GPS Measurements

Author: Renaud Fallourd, Olivier Harant, Emmanuel Trouve, Jean-Marie Nicolas, Michel Gay, Andrea Walpersdorf, Jean-Louis Mugnier, Jonathan Serafini, Diana Rosu, Lionel Bombrun, Gabriel Vasile, Nathalie Cotte, Flavien Vernier, Florence Tupin, Luc Moreau, Philippe Bolon, Laboratoire d'Informatique, Systèmes, Traitement de l'Information et de la Connaissance (LISTIC), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), Département Images et Signal (GIPSA-DIS), Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Laboratoire Traitement et Communication de l'Information (LTCI), Télécom ParisTech-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), GIPSA-Services (GIPSA-Services), Cycle sismique et déformations transitoires, Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Tectonique reliefs et bassins, Géopôle du Pacifique Sud (GePaSUD), Université de la Polynésie Française (UPF), Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), and Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Backscatter, [SDE.MCG]Environmental Sciences/Global Changes, offset tracking, 0211 other engineering and technologies, 02 engineering and technology, 01 natural sciences, Displacement (vector), motion estimation, Corner reflector, Computers in Earth Sciences, Image resolution, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, geography, geography.geographical_feature_category, business.industry, Corner reflector (CR), Glacier, temperate glacier, synthetic aperture radar (SAR), Snow, Geodesy, Glaciology, Global Positioning System, high resolution (HR), business, Geology
Abstract: International audience; A new generation of space-borne SAR sensors were launched in 2006-2007 with ALOS, TerraSAR-X, COSMO-Sky-Med and RadarSat-2 satellites. The data available in different bands (L, C and X bands), with High Resolution (HR) or multi-polarization modes offer new possibilities to monitor glacier displacement and surface evolution by SAR remote sensing. In this paper, the first results obtained with TerraSAR-X HR SAR image time series acquired over the temperate glaciers of the Chamonix Mont-Blanc test site are presented. This area involves well-known temperate glaciers which have been monitored and instrumented i.e. stakes for annual displacement/ablation, GPS for surface displacement and cavitometer for basal displacement, for more than 50 years. The potential of 11-day repeated X-band HR SAR data for Alpine glacier monitoring is investigated by a combined use of in situ measurements and multi-temporal images. Interpretations of HR images, analysis of interferometric pairs and performance assessments of target/texture tracking methods for glacier motion estimation are presented. The results obtained with four time series covering the Chamonix Mont-Blanc glaciers over one year show that the phase information is rarely preserved after 11 days on such glaciers, whereas the high resolution intensity information allows the main glacier features to be observed and displacement fields on the textured areas to be derived.
Published: 2011
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43. The kinematics of the Zagros Mountains (Iran)

Author: P. van Beek, F. Tavakoli, Mohammad Tatar, B. Oveisi, Olivier Bellier, F. Yamini-Fard, Jérôme Lavé, Denis Hatzfeld, Christine Authemayou, and A. Walpersdorf
Subjects: geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Elevation, Geology, Ocean Engineering, Induced seismicity, Fault (geology), Deformation (meteorology), 010502 geochemistry & geophysics, 01 natural sciences, Tectonics, Basement (geology), Echelon formation, Sedimentary rock, Seismology, 0105 earth and related environmental sciences, Water Science and Technology
Abstract: We present a synthesis of recently conducted tectonic, global positioning system (GPS), geomorphological and seismic studies to describe the kinematics of the Zagros mountain belt, with a special focus on the transverse right-lateral strike-slip Kazerun Fault System (KFS). Both the seismicity and present-day deformation (as observed from tectonics, geomorphology and GPS) appear to concentrate near the 1000 m elevation contour, suggesting that basement and shallow deformation are related. This observation supports a thick-skinned model of southwestward propagation of deformation, starting from the Main Zagros Reverse Fault. The KFS distributes right-lateral strike-slip motion of the Main Recent Fault onto several segments located in an en echelon system to the east. We observe a marked difference in the kinematics of the Zagros across the Kazerun Fault System. To the NW, in the North Zagros, present-day deformation is partitioned between localized strike-slip motion on the Main Recent Fault and shortening located on the deformation front. To the SE, in the Central Zagros, strike-slip motion is distributed on several branches of the KFS. The decoupling of the Hormuz Salt layer, restricted to the east of the KFS and favouring the spreading of the sedimentary cover, cannot be the only cause of this distributed mechanism because seismicity (and therefore basement deformation) is associated with all active strike-slip faults, including those to the east of the Kazerun Fault System.
Published: 2010
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44. Large-scale velocity field and strain tensor in Iran inferred from GPS measurements: new insight for the present-day deformation pattern within NE Iran

Author: Mohammad Anvari, Hamid Reza Nankali, Y. Djamour, F. Tavakoli, Sébastien Van Gorp, Frédéric Masson, A. Walpersdorf, Marc Daignières, Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Geodynamic Department, National Cartographic Center [Iran] (NCC), Khorasan Department of NCC, NCC, Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre [2011-2015] (ISTerre [2011-2015]), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Observatoire des Sciences de l'Univers de Grenoble [1985-2015] (OSUG [1985-2015]), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Laboratoire Central des Ponts et Chaussées (LCPC)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, 010504 meteorology & atmospheric sciences, Deformation (mechanics), Continental collision, GPS, Infinitesimal strain theory, Iran, Present day, Structural basin, 010502 geochemistry & geophysics, Geodesy, Collision zone, Block (meteorology), 01 natural sciences, Tectonics, Geophysics, continental collision, Geochemistry and Petrology, Geology, Seismology, 0105 earth and related environmental sciences
Abstract: International audience; A network of 26 GPS sites was implemented in Iran and Northern Oman to measure displacements in this part of the Arabia–Eurasia collision zone. We present the GPS velocity field obtained from three surveys performed in 1999 September, 2001 October and 2005 September and the deduced strain tensor. This study refines previous studies inferred from only the two first surveys. Improvements are significant in NE Iran. The present-day shortening rate across the mountain belts of NE Iran is estimated to 5 ± 1 mm yr−1 at about N11°, 2 ± 1 mm yr−1 of NS shortening across the eastern Kopet Dag and 3 ± 1 mm yr−1 of NS shortening across Binalud and Kuh-e-Sorkh. Our GPS measurements emphasize the varying character of the Kopet Dag deformation between its southeastern part with prevailing thrusting at low rates and its northwestern part with dominant strike-slip activity at increasing rates. The principal axes of the horizontal strain tensor appears very homogeneous from the Zagros to the Alborz and the Kopet-Dag (N20°) and in eastern Iran (Makran and Lut block: N30°). Only NW Iran suffers a variable strain pattern which seems to wrap the Caspian basin. The strain tensor map underlines the existence of large homogeneous tectonic provinces in terms of style and amplitude of the deformation.
Published: 2007
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45. Difference in the GPS deformation pattern of North and Central Zagros (Iran)

Author: Jean Chéry, F. Nilforoushan, Denis Hatzfeld, Philippe Vernant, F. Tavakoli, F. Masson, H. Nankali, Mohammad Tatar, Andrea Walpersdorf, Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Centre National de la Recherche Scientifique (CNRS), National Cartographic Center [Iran] (NCC), International Institute of Earthquake Engineering and Seismology [Tehran] (IIEES), Laboratoire Dynamique de la Lithosphère (LDL), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)
Subjects: Shore, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Satellite geodesy, fault motion, Slip (materials science), Induced seismicity, 010502 geochemistry & geophysics, Zagros, 01 natural sciences, Geophysics, Sinistral and dextral, Shear (geology), [SDU]Sciences of the Universe [physics], Geochemistry and Petrology, plate convergence, Sedimentary rock, continental deformation, Zagros fold and thrust belt, Global Positioning System (GPS), Geology, Seismology, 0105 earth and related environmental sciences
Abstract: International audience; Measurements on either side of the Kazerun fault system in the Zagros Mountain Belt, Iran, show that the accommodation of the convergence of the Arabian and Eurasian Plates differs across the region. In northwest Zagros, the deformation is partitioned as 3–6 mm yr−1 of shortening perpendicular to the axis of the mountain belt, and 4–6 mm yr−1 of dextral strike-slip motion on northwest–southeast trending faults. No individual strike-slip fault seems to slip at a rate higher than ~2 mm yr−1. In southeast Zagros, the deformation is pure shortening of 8 ± 2 mm yr−1 occurring perpendicular to the simple folded belt and restricted to the Persian Gulf shore. The fact that most of the deformation is located in front of the simple folded belt, close to the Persian Gulf, while seismicity is more widely spread across the mountain belt, confirms the decoupling of the surface sedimentary layers from the seismogenic basement. A comparison with the folding and topography corroborates a southwestward propagation of the surface deformation. The difference in deformation between the two regions suggests that right-lateral shear cumulates on the north–south trending Kazerun strike-slip fault system to 6 ± 2 mm yr−1.
Published: 2006
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46. Microbial communities near the oxic/anoxic interface in the hydrothermal system of Vulcano Island, Italy

Author: Jan P. Amend, Dirk deBeer, Sergio Gurrieri, Eva Walpersdorf, and Antje Rusch
Subjects: fungi, Sediment, Geology, Anoxic waters, Hydrothermal circulation, Paleontology, Pore water pressure, Microbial population biology, Geochemistry and Petrology, Benthic zone, Environmental chemistry, Subaerial, Seawater
Abstract: Hydrothermal fluids and sediments from subaerial and shallow submarine sites at Vulcano Island, Italy were investigated for relations between the thermophilic microbial communities, as analysed by fluorescence in situ hybridization, and their geochemical environment, as assessed by photometry, chromatography, and in situ microsensor measurements. Mixing between hydrothermal fluids and seawater in the sediment pore space was reflected in the chemical composition of the emitted fluids, in depth profiles of pore water oxygen and sulfide concentrations, and in the structure of the benthic microbial community. Organic compounds did not accumulate in the vent fluids (
Published: 2005
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47. Efficiency of natural calcite precipitation compared to lake marl application used for water quality improvement in an eutrophic lake

Author: Thomas Neumann, Eva Walpersdorf, and Doris Stüben
Subjects: chemistry.chemical_classification, Calcite, Mineralogy, engineering.material, Pollution, chemistry.chemical_compound, Water column, chemistry, Geochemistry and Petrology, Marl, engineering, Environmental Chemistry, Carbonate, Organic matter, Water quality, Eutrophication, Geology, Lime
Abstract: Since the 1980s, several in-lake restoration methods for eutrophied lakes have been developed based on artificially induced calcite precipitation and lime additions. The aim of these measures is to improve water quality and reduce the incidence of cyanobacterial blooms by increasing P adsorption and removal through natural calcite precipitation. The authors compared the relative efficiencies of lake marl application and natural calcite precipitation in immobilizing P, Mn and Fe in Lake Arendsee, northeastern Germany, and their subsequent value as a tool for managing eutrophication. Microprobe investigations of element distributions in calcite minerals of laminae precipitated annually during several years before and two years following the restoration suggest that recently grown biogenic calcites were more efficient at the co-precipitation and immobilization of P, Fe and Mn. The lake marl applied as 16% calcite/water mixture proved unsuitable as a restoration tool because of its coarse grain size mainly in the range of 20–1000 μm and associated organic matter which reduced its suspension time and sorption reaction rates in the water column. In Lake Arendsee or in similar eutrophic hardwater lakes with fast internal P recycling by rapid degradation of autochthonous organic matter in the water column and at the sediment surface (sedimentary TOC:TP ratios of 200 or more), biogenic calcites provide almost permanent P, Fe and Mn retention in the sediments. The study shows that epilimnetic additions of pure CaCO 3 seed crystals comparable to natural calcite precipitation are the most effective for improving water quality. Small CaCO 3 crystals exhibit a larger reactive surface, and thus, incorporate adsorbed dissolved nutrients and trace metals more rapidly during growth. However, in-lake water quality management strategies work best only if external point and non-point nutrient sources are reduced or diverted.
Published: 2004
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48. Coherence between geodetic and seismic deformation in a context of slow tectonic activity (SW Alps, France)

Author: Z. Mousavi, D. Souami, H. Dyer, P. Vaudey, Stéphane Baize, Céline Beauval, G. Daniel, Jean-Robert Grasso, G. Menard, Pascale Bascou, Christophe Voisin, J. Martinod, Sébastien Hok, O. Hautecoeur, A. Walpersdorf, Agnès Helmstetter, P. Collard, Christian Sue, Magali Rizza, L. Thirard, Lucie Rolland, Fleur Ponton, Nathalie Cotte, Mickael Langlais, Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Mécanique des failles, Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Archéosphère, Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Laboratoire Magmas et Volcans (LMV), Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre de Mathématiques Laurent Schwartz (CMLS), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Ingénierie des Mouvements du Sol et des Risques Naturels (IMSRN), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut des Sciences de la Terre ( ISTerre ), Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers ( INSU - CNRS ) -Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux ( IFSTTAR ) -Université Joseph Fourier - Grenoble 1 ( UJF ), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Institut de Radioprotection et de Sûreté Nucléaire ( IRSN ), Observatoire des Sciences de l'Univers de Grenoble ( OSUG ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers ( INSU - CNRS ) -Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux ( IFSTTAR ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers ( INSU - CNRS ) -Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux ( IFSTTAR ) -Université Joseph Fourier - Grenoble 1 ( UJF ), Université des Antilles et de la Guyane ( UAG ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université de Montpellier ( UM ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de chimie de coordination ( LCC ), Centre National de la Recherche Scientifique ( CNRS ), Groupe d'étude de l'atmosphère météorologique ( CNRM-GAME ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Météo France-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Géophysique Interne et Tectonophysique ( LGIT ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Laboratoire Central des Ponts et Chaussées ( LCPC ) -Institut des Sciences de la Terre ( ISTerre ), Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers ( INSU - CNRS ) -Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux ( IFSTTAR ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux ( IFSTTAR ), Laboratoire Magmas et Volcans ( LMV ), Université Blaise Pascal - Clermont-Ferrand 2 ( UBP ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université Jean Monnet [Saint-Étienne] ( UJM ) -Centre National de la Recherche Scientifique ( CNRS ), Centre européen de recherche et d'enseignement de géosciences de l'environnement ( CEREGE ), Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Collège de France ( CdF ) -Institut National de la Recherche Agronomique ( INRA ) -Institut national des sciences de l'Univers ( INSU - CNRS ), Géoazur ( GEOAZUR ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Systèmes de Référence Temps Espace ( SYRTE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Centre National de la Recherche Scientifique ( CNRS ), Centre de Mathématiques Laurent Schwartz ( CMLS ), École polytechnique ( X ) -Centre National de la Recherche Scientifique ( CNRS ), Géosciences Environnement Toulouse ( GET ), and Institut de Recherche pour le Développement ( IRD ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS )
Subjects: 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], GPS, [SDE.MCG]Environmental Sciences/Global Changes, Context (language use), Deformation (meteorology), Crustal deformation, 010502 geochemistry & geophysics, 01 natural sciences, Uplift, [ SDU.STU.GP ] Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Extension, 0105 earth and related environmental sciences, Earth-Surface Processes, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, business.industry, Western Alps, Seismotectonics, Geodetic datum, [ SDU.STU.TE ] Sciences of the Universe [physics]/Earth Sciences/Tectonics, Geodesy, [ SDE.MCG ] Environmental Sciences/Global Changes, Tectonics, Plate tectonics, Geophysics, Sinistral and dextral, Global Positioning System, business, Geology, Seismology
Abstract: International audience; A dense, local network of 30 geodetic markers covering a 50 × 60 km2 area in the southwestern European Alps (Briançon region) has been temporarily surveyed in 1996, 2006 and 2011 by GPS. The aim is to measure the current deformation in this seismically active area. The study zone is characterized by a majority of extensional and dextral focal mechanisms, along north–south to N160 oriented faults. The combined analysis of the three measurement campaigns over 15 years and up to 16 years of permanent GPS data from the French RENAG network now enables to assess horizontal velocities below 1 mm/year within the local network. The long observation interval and the redundancy of the dense campaign network measurement help to constrain a significant local deformation pattern in the Briançon region, yielding an average E–W extension of 16 ± 11 nanostrain/year. We compare the geodetic deformation field to the seismic deformation rate cumulated over 37 years, and obtain good coherencies both in amplitude and direction. Moreover, the horizontal deformation localized in the Briançon region represents a major part of the Adriatic-European relative plate motion. However, the average uplift of the network in an extensional setting needs the presence of buoyancy forces in addition to plate tectonics.
Published: 2015
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49. Lateral Variations of Interplate Coupling along the Mexican Subduction Interface: Relationships with Long-Term Morphology and Fault Zone Mechanical Properties

Author: Nadaya Cubas, Vladimir Kostoglodov, Charles DeMets, B. Rousset, Nathalie Cotte, A. Walpersdorf, Mathilde Radiguet, Anne Socquet, Cécile Lasserre, Michel Campillo, S. E. Graham, Enrique Cabral-Cano, Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Déformations, sismotectonique, imagerie, relief (DéSIR), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Planetary Sciences [Cambridge, USA] (EPS), Harvard University [Cambridge], Department of Geoscience, University of Wisconsin-Madison, Instituto de Geofísica, Universidad Nacional Autónoma de México (UNAM), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Harvard University, and Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM)
Subjects: 010504 meteorology & atmospheric sciences, Subduction, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Slip (materials science), 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Seismic hazard, Shear (geology), 13. Climate action, Geochemistry and Petrology, Trench, Bathymetry, Deformation (engineering), Forearc, Seismology, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Although patterns of interseismic strain accumulation above subduction zones are now routinely characterised using geodetic measurements, their physical origin, persistency through time, and relationships to seismic hazard and long-term deformation are still debated. Here, we use GPS and morphological observations from southern Mexico to explore potential mechanical links between variations in inter-SSE (in between slow slip events) coupling along the Mexico subduction zone and the long-term topography of the coastal regions from Guerrero to Oaxaca. Inter-SSE coupling solutions for two different geometries of the subduction interface are derived from an inversion of continuous GPS time series corrected from slow slip events. They reveal strong along-strike variations in the shallow coupling (i.e. at depths down to 25 km), with high-coupling zones (coupling >0.7) alternating with low-coupling zones (coupling 0.7) and transitions to uncoupled, steady slip at a relatively uniform $\sim $175-km inland from the trench. Along-strike variations in the coast-to-trench distances are strongly correlated with the GPS-derived forearc coupling variations. To explore a mechanical explanation for this correlation, we apply Coulomb wedge theory, constrained by local topographic, bathymetric, and subducting-slab slopes. Critical state areas, i.e. areas where the inner subduction wedge deforms, are spatially correlated with transitions at shallow depth between uncoupled and coupled areas of the subduction interface. Two end-member models are considered to explain the correlation between coast-to-trench distances and along-strike variations in the inter-SSE coupling. The first postulates that the inter-SSE elastic strain is partitioned between slip along the subduction interface and homogeneous plastic permanent deformation of the upper plate. In the second, permanent plastic deformation is postulated to depend on frictional transitions along the subduction plate interface. Based on the location and friction values of the critical state areas identified by our Coulomb wedge analysis, we parameterise frictional transitions in plastic-static models of deformation over several seismic cycles. This predicts strong shear dissipation above frictional transitions on the subduction interface. The comparison of modelled surface displacements over a critical zone at a frictional transition and over a stable area with no internal wedge deformation shows differences of long-term uplift consistent with the observed along-strike variations in the coast-to-trench distances. Our work favours a model in which frictional asperities partly control short-term inter-SSE coupling as measured by geodesy and in which those asperities persist through time.
Published: 2015
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50. Stable isotopes in recent sediments of Lake Arendsee, NE Germany: response to eutrophication and remediation measures

Author: Eva Walpersdorf, Helmar Kunzendorf, Thomas Neumann, Andrea Stögbauer, and Doris Stüben
Subjects: chemistry.chemical_classification, Varve, Stable isotope ratio, Paleontology, Sediment, Authigenic, Plankton, Oceanography, chemistry, Isotopes of carbon, Organic matter, Eutrophication, Ecology, Evolution, Behavior and Systematics, Geology, Earth-Surface Processes
Abstract: Recent sediments of Lake Arendsee, a small eutrophic lake in NE Germany, were examined in high temporal resolution in order to investigate the applicability of stable isotopes as proxies to trace paleoenvironmental conditions. The age model of the sediment core is based on varve counting and 137Cs/210Pb dating and reveals that the sedimentary record covers the last 70 years, during which the lake has undergone major changes in productivity and eutrophication in response to nutrient loading. Since 1965, TOC, TIC, TN and TP accumulation rates in general reflect the change from oligo-/mesotrophic to eutrophic level. The isotopic compositions of autochthonous organic matter and authigenic calcite (whitings) demonstrate that carbon isotope fractionation takes place in a CO2-limited pool. In accordance with the historical limnological observations, enhanced eutrophication is reflected by δ13CTOC increases of over 3‰ from 1934 to 1985 as a result of less 12C/13C fractionation by photosynthesis during intense primary productivity. Decreasing δ13CTIC values indicate that biogenically induced calcite formation occurred during enhanced primary production accompanied by CO2 limitation. The gradual trend to more light nitrogen isotopic signatures towards the sediment surface reflects the dominance of air nitrogen fixation of cyanobacteria blooms during the last decades. The δ18OTIC distribution suggests that plankton blooms between 1934 and 1978 had shifted towards the early season with lower temperatures as a result of increasing nutrient level, which subsequently favor plankton blooms even in colder waters. Since the mid 1980s, decreasing δ13CTOC and increasing δ13CTIC values since 1985 indicate a more efficient 12C/13C fractionation during photosynthesis with no CO2 limitation. This improvement in water quality is in accordance with several remediation measures carried out since the late 1970s. Linear isotopic trends are interrupted by high TIC, TOC, TN and TP accumulation rates in the early 1970s, which can be clearly attributed to the artificial drainage of a nearby wetland carried out during that time. This event can be considered an important external source for nutrient-loaded water and particulate matter and is displayed by significantly heavier δ13CTIC and δ18OTIC values in the sedimentary record.
Published: 2002
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