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26 results on '"Rosas-Carbajal, M."'

1. Abrupt changes of hydrothermal activity in a lava dome detected by combined seismic and muon monitoring

Author

Gonidec, Y. Le, Rosas-Carbajal, M., d'Ars, J. de Bremond, Carlus, B., Ianigro, J. -C., Kergosien, B., Marteau, J., and Gibert, D.

Subjects
Physics - Geophysics, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

The recent 2014 eruption of the Ontake volcano in Japan recalled that hydrothermal fields of moderately active volcanoes have an unpredictable and hazardous behavior that may endanger human beings. Steam blasts can expel devastating ejecta and create craters of several tens of meters. The management of such hydrothermal hazards in populated areas is problematic because of their very short time constants. At present no precursory signal is clearly identified as a potential warning of imminent danger. Here we show how the combination of seismic noise monitoring and muon density tomography allows to detect, with an unprecedented space and time resolution, the increase of activity of a hydrothermal focus located 50 to 100 m below the summit of an active volcano, the La Soufri\`ere of Guadeloupe, in the Lesser Antilles. The present study deals with hydrothermal activity events at timescales of few hours to few days. We show how the combination of those two methods improves the risk evaluation of short-term hazards and the localization of the involved volumes in the volcano. We anticipate that the deployment of networks of various sensors including temperature probes, seismic antennas and cosmic muon telescopes around such volcanoes could valuably contribute to early warning decisions., Comment: 16 pages including 4 pages supplementary information, Nature Scientific Reports, November 2018

Published
2018

2. Forward scattering effects on muon imaging

Author

Gómez, H., Gibert, D., Goy, C., Jourde, K., Karyotakis, Y., Katsanevas, S., Marteau, J., Rosas-Carbajal, M., and Tonazzo, A.

Subjects
Physics - Instrumentation and Detectors
Abstract

Muon imaging is one of the most promising non-invasive techniques for density structure scanning, specially for large objects reaching the kilometre scale. It has already interesting applications in different fields like geophysics or nuclear safety and has been proposed for some others like engineering or archaeology. One of the approaches of this technique is based on the well-known radiography principle, by reconstructing the incident direction of the detected muons after crossing the studied objects. In this case, muons detected after a previous forward scattering on the object surface represent an irreducible background noise, leading to a bias on the measurement and consequently on the reconstruction of the object mean density. Therefore, a prior characterization of this effect represents valuable information to conveniently correct the obtained results. Although the muon scattering process has been already theoretically described, a general study of this process has been carried out based on Monte Carlo simulations, resulting in a versatile tool to evaluate this effect for different object geometries and compositions. As an example, these simulations have been used to evaluate the impact of forward scattered muons on two different applications of muon imaging: archaeology and volcanology, revealing a significant impact on the latter case. The general way in which all the tools used have been developed can allow to make equivalent studies in the future for other muon imaging applications following the same procedure., Comment: 16 pages, 6 figures

Published
2017
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3. Two-dimensional probabilistic inversion of plane-wave electromagnetic data: Methodology, model constraints and joint inversion with electrical resistivity data

Author

Rosas-Carbajal, M., Linde, N., Kalscheuer, T., and Vrugt, J. A.

Subjects
Physics - Geophysics
Abstract

Probabilistic inversion methods based on Markov chain Monte Carlo (MCMC) simulation are well suited to quantify parameter and model uncertainty of nonlinear inverse problems. Yet, application of such methods to CPU-intensive forward models can be a daunting task, particularly if the parameter space is high dimensional. Here, we present a two-dimensional (2D) pixel-based MCMC inversion of plane-wave electromagnetic (EM) data. Using synthetic data, we investigate how model parameter uncertainty depends on model structure constraints using different norms of the likelihood function and the model constraints, and study the added benefits of joint inversion of EM and electrical resistivity tomography (ERT) data. Our results demonstrate that model structure constraints are a necessity to stabilize the MCMC inversion results of a highly-discretized model. These constraints decrease model parameter uncertainty and facilitate model interpretation. A drawback is that these constraints may lead to posterior distributions that do not fully include the true underlying model, because some of its features exhibit a low sensitivity to the EM data, and hence are difficult to resolve. This problem can be partly mitigated if the plane-wave EM data is augmented with ERT observations. The hierarchical Bayesian inverse formulation introduced and used herein is able to successfully recover the probabilistic properties of the measurement data errors and a model regularization weight. Application of the proposed inversion methodology to field data from an aquifer demonstrates that the posterior mean model realization is very similar to that derived from a deterministic inversion with similar model constraints.

Published
2017
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4. Two-dimensional probabilistic inversion of plane-wave electromagnetic data: Methodology, model constraints and joint inversion with electrical resistivity data

Author

Rosas-Carbajal, M, Linde, N, Kalscheuer, T, and Vrugt, JA

Subjects
Inverse theory, Probability distributions, Non-linear electromagnetics, physics.geo-ph, Geochemistry & Geophysics, Geophysics, Geology, Geomatic Engineering
Abstract

Probabilistic inversion methods based on Markov chain Monte Carlo (MCMC) simulation are well suited to quantify parameter and model uncertainty of nonlinear inverse problems. Yet, application of such methods to CPU-intensive forward models can be a daunting task, particularly if the parameter space is high dimensional. Here, we present a 2-D pixel-based MCMC inversion of plane-wave electromagnetic (EM) data. Using synthetic data, we investigate how model parameter uncertainty depends on model structure constraints using different norms of the likelihood function and the model constraints, and study the added benefits of joint inversion of EM and electrical resistivity tomography (ERT) data. Our results demonstrate that model structure constraints are necessary to stabilize the MCMC inversion results of a highly discretized model. These constraints decrease model parameter uncertainty and facilitate model interpretation. A drawback is that these constraints may lead to posterior distributions that do not fully include the true underlying model, because some of its features exhibit a low sensitivity to the EM data, and hence are difficult to resolve. This problem can be partly mitigated if the plane-wave EM data is augmented with ERT observations. The hierarchical Bayesian inverse formulation introduced and used herein is able to successfully recover the probabilistic properties of the measurement data errors and a model regularization weight. Application of the proposed inversion methodology to field data from an aquifer demonstrates that the posterior mean model realization is very similar to that derived from a deterministic inversion with similar model constraints. © The Authors 2013.

Published
2014

7. Middle-atmosphere Dynamics Studied with a Portable Muon Detector at the Mont Terri Underground Rock Laboratory, Switzerland

Author

Rosas-Carbajal, M., Tramontini, M., Nussbaum, C., Gibert, Dominique, Marteau, J., Universidad Nacional de la Plata [Argentine] (UNLP), Institut de Physique du Globe de Paris (IPGP), 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), CSIRO Earth Science and Resource Engineering Perth, Géosciences Rennes (GR), Université de Rennes 1 (UR1), 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), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), American Geophysical Union, 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), CSIRO Earth Science and Resource Engineering [Perth ], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), 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), 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), 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), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Institut de Physique des 2 Infinis de Lyon (IP2I Lyon)

Subjects
8494 Instruments and techniques, VOLCANOLOGY, Physics::Instrumentation and Detectors, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, High Energy Physics::Experiment, 0994 Instruments and techniques, 0910 Data processing, EXPLORATION GEOPHYSICS, 0933 Remote sensing, Physics::Atmospheric and Oceanic Physics
Abstract

International audience; In the past years, large particle-physics experiments have shown that muon rate variations detected in underground laboratories are sensitive to regional, middle-atmosphere temperature variations. Potential applications include tracking short-term atmosphere dynamics, such as Sudden Stratospheric Warmings. In this work we use a portable muon detector conceived for muon tomography for geophysical applications, that is, imaging geological objects by quantifying the screening effect they have on the natural flux of cosmic muons. We study seasonal and short-term variations in the moun rate measured in the Mont Terri underground rock laboratory. This site is located in the Jura Mountains in north-western Switzerland, at a depth of ~300 meters below the Earth's surface. We found that the sensitivity to middle-atmosphere dynamics is not only limited to large-scale particle detectors, which are specifically built for neutrino and high-energy particle experiments under high-opacity conditions. Analyzing a year of continuous muon measurements, we found that changes in the thermal state of the atmosphere represent the largest cause of muon rate variations. Furthermore, muon rate variations are also sensitive to the abnormal atmosphere heating in January-February 2017, associated to a Sudden Stratospheric Warming. The estimates of the effective temperature coefficient for our particular case agree with theoretical models and with those calculated from large neutrino experiments under comparable conditions. Finally, we discuss the implications of our observations both for Atmospheric Sciences and for the Geophysics community, the latter aiming to characterize density variations in the subsurface with muon data.

Published
2019

8. Including magnetotelluric data into multi-observable probabilistic inversion: implications for the physical state and water content of the continental lithosphereIncluding 3D magnetoteluric data into joint probabilistic inversions

Author

Manassero, Constanza, Afonso, Juan Carlos, Zyserman, Fabio, Zlotnik, Sergio|||0000-0001-9674-8950, Rosas-Carbajal, M., Thiel, S., Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. LACÀN - Mètodes Numèrics en Ciències Aplicades i Enginyeria

Subjects
Enginyeria civil::Geologia [Àrees temàtiques de la UPC], Geophysics--Statistical methods, Geofísica -- Estadística matemàtica
Abstract

Multi-observable probabilistic inversion [e.g. 1,2,3] is providing new insights into the physicochemical structure of the lithosphere and its complex interaction with the underlying convecting upper mantle. Of particular importance is the inclusion of 3D magnetotelluric (MT) data into the joint inversion, as it provides complementary information not only on the thermal structure but also on water content and fluid pathways, which are difficult to constrain with other observables. MT holds, therefore, great potential for understanding and imaging the complex fluid-rock interactions responsible for mineralization events due to its sensitivity to water and other volatiles. However, in order to isolate the effect of fluids from other potential compositional and thermal “background” effects, MT data needs to be informed by other data sets such as seismic and gravity data. In order to implement MT data into multi-observable probabilistic inversions for the 3D imaging of deep thermochemical anomalies and fluid pathways in the Earth, we first need to solve the problem of computational efficiency in solving Maxwell’s equations in 3D in a probabilistic way. For this, we combine state-of-the-art probabilistic inversion methods, parallel MT solvers [4] and advanced reduced order modelling techniques to obtain fast, yet accurate, solutions to both the MT inversion and the full 3D joint inversion problem, which typically includes the solution of seismic, gravity, heat transfer, and mantle convection forward problems [e.g. 3]. Such a probabilistic formalism offers a natural framework to assess non-uniqueness and uncertainties affecting the inversion, which are otherwise hard to quantify using traditional inversion methods. In this contribution we report on recent progress made towards the above goals, including thorough benchmarks, illustrative examples and preliminary results of a case study. These results indicate that a conceptual and numerical platform capable of including 3D MT data into multi-observable probabilistic inversions is a reachable aim.

Published
2019

9. Les risques volcaniques au XXIe siècle : surveiller et prévoir ; l’exemple de l’OVSG

Author

Jessop, D. E., Moretti, R., Severine Moune, Magali Bonifacie, Burtin, A., B Chabalier, J., Deroussi, S., C Komorowski, J., Rosas-Carbajal, M., Bosson, A., Didier, T., Kitou, T., Lemarchand, A., Robert, V., Ovsg, M., and Institut de Physique du Globe de Paris

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

11. Including magnetotelluric data into multi-observable probabilistic inversion: implications for the physical state and water content of the continental lithosphereIncluding 3D magnetoteluric data into joint probabilistic inversions

Author

Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. LACÀN - Mètodes Numèrics en Ciències Aplicades i Enginyeria, Manassero, Constanza, Afonso, Juan Carlos, Zyserman, Fabio, Zlotnik, Sergio, Rosas-Carbajal, M., Thiel, S., Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. LACÀN - Mètodes Numèrics en Ciències Aplicades i Enginyeria, Manassero, Constanza, Afonso, Juan Carlos, Zyserman, Fabio, Zlotnik, Sergio, Rosas-Carbajal, M., and Thiel, S.

Abstract

Multi-observable probabilistic inversion [e.g. 1,2,3] is providing new insights into the physicochemical structure of the lithosphere and its complex interaction with the underlying convecting upper mantle. Of particular importance is the inclusion of 3D magnetotelluric (MT) data into the joint inversion, as it provides complementary information not only on the thermal structure but also on water content and fluid pathways, which are difficult to constrain with other observables. MT holds, therefore, great potential for understanding and imaging the complex fluid-rock interactions responsible for mineralization events due to its sensitivity to water and other volatiles. However, in order to isolate the effect of fluids from other potential compositional and thermal “background” effects, MT data needs to be informed by other data sets such as seismic and gravity data. In order to implement MT data into multi-observable probabilistic inversions for the 3D imaging of deep thermochemical anomalies and fluid pathways in the Earth, we first need to solve the problem of computational efficiency in solving Maxwell’s equations in 3D in a probabilistic way. For this, we combine state-of-the-art probabilistic inversion methods, parallel MT solvers [4] and advanced reduced order modelling techniques to obtain fast, yet accurate, solutions to both the MT inversion and the full 3D joint inversion problem, which typically includes the solution of seismic, gravity, heat transfer, and mantle convection forward problems [e.g. 3]. Such a probabilistic formalism offers a natural framework to assess non-uniqueness and uncertainties affecting the inversion, which are otherwise hard to quantify using traditional inversion methods. In this contribution we report on recent progress made towards the above goals, including thorough benchmarks, illustrative examples and preliminary results of a case study. These results indicate that a conceptual and numerical platform capable of including 3D, Postprint (published version)

Published
2019

12. Three-dimensional density structure of La Soufrière de Guadeloupe lava dome from simultaneous muon radiographies and gravity data

Author

Rosas-Carbajal, M., Jourde, K., De Bremond D'Ars, Jean, Carlus, B., Gibert, Dominique, Le Gonidec, Yves, Ianigro, J.-C., Komorowski, J.-C., Marteau, J., 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), 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), Géosciences Rennes (GR), 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), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS), Neutrinos (NEUTRINOS), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), 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), 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), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), 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), 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), and Neutrinos

Subjects
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

15. Forward scattering effects on muon imaging

Author

Gómez, H., primary, Gibert, D., additional, Goy, C., additional, Jourde, K., additional, Karyotakis, Y., additional, Katsanevas, S., additional, Marteau, J., additional, Rosas-Carbajal, M., additional, and Tonazzo, A., additional

Published
2017
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17. Probabilistic 3-D time-lapse inversion of magnetotelluric data: application to an enhanced geothermal system

Author

Rosas-Carbajal, M., Linde, N., Peacock, J., Zyserman, F. I., Kalscheuer, Thomas, Thiel, S., Rosas-Carbajal, M., Linde, N., Peacock, J., Zyserman, F. I., Kalscheuer, Thomas, and Thiel, S.

Abstract

Surface-based monitoring of mass transfer caused by injections and extractions in deep boreholes is crucial to maximize oil, gas and geothermal production. Inductive electromagnetic methods, such as magnetotellurics, are appealing for these applications due to their large penetration depths and sensitivity to changes in fluid conductivity and fracture connectivity. In this work, we propose a 3-D Markov chain Monte Carlo inversion of time-lapse magnetotelluric data to image mass transfer following a saline fluid injection. The inversion estimates the posterior probability density function of the resulting plume, and thereby quantifies model uncertainty. To decrease computation times, we base the parametrization on a reduced Legendre moment decomposition of the plume. A synthetic test shows that our methodology is effective when the electrical resistivity structure prior to the injection is well known. The centre of mass and spread of the plume are well retrieved. We then apply our inversion strategy to an injection experiment in an enhanced geothermal system at Paralana, South Australia, and compare it to a 3-D deterministic time-lapse inversion. The latter retrieves resistivity changes that are more shallow than the actual injection interval, whereas the probabilistic inversion retrieves plumes that are located at the correct depths and oriented in a preferential north–south direction. To explain the time-lapse data, the inversion requires unrealistically large resistivity changes with respect to the base model. We suggest that this is partly explained by unaccounted subsurface heterogeneities in the base model from which time-lapse changes are inferred.

Published
2015
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19. Observation of the Dynamics of Hydrothermal Activity in La Soufrière of Guadeloupe Volcano with Joint Muography, Gravimetry, Electrical Resistivity Tomography, Seismic and Temperature Monitoring

Author

Dominique Gibert, Jean Bremond d'Ars, Bruno Carlus, Sébastien Deroussi, Jean‐Christophe Ianigro, David E. Jessop, Kevin Jourde, Bruno Kergosien, Yves Le Gonidec, Nolwenn Lesparre, Jacques Marteau, Roberto Moretti, Florence Nicollin, Marina Rosas‐Carbajal, László Oláh, Hiroyuki K. M. Tanaka, Dezső Varga, Gibert, D., de Bremond d'Ars, J., Carlus, B., Deroussi, S., Ianigro, J. -C., Jessop, D. E., Jourde, K., Kergosien, B., Le Gonidec, Y., Lesparre, N., Marteau, J., Moretti, R., Nicollin, F., Rosas-Carbajal, M., 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), 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), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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), CEA Grenoble, Université de Strasbourg (UNISTRA), László Oláh, Hiroyuki K. M, and Tanaka Dezső Varga

Subjects
Gravimetry, Fumerole temperature, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Geophysical method, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Electrical resistivity tomography, Seismic monitoring, Volcanic hydrothermal systems, Muon tomography
Abstract

International audience; Muography uses muons contained in the natural cosmic rays to determine the density of rock volumes. The measurements consist of counting the muons emerging from the target to determine the screening effect produced by the rock. Since the larger the rock thickness, the smaller the number of muons able to cross, the time resolution that can be achieved by muography to monitor density changes is on the order of one or two weeks for kilometer-sized volcanoes. This limitation of the method can be reduced by joining muography with high time-resolution measurements like passive seismic monitoring. In the case of structural imaging, muography benefits from the fact that muon trajectories are linear, making the tomography problem simpler than for other geophysical techniques like electrical resistivity tomography. Experiments performed on La Soufrière of Guadeloupe volcano are described to show how muography can be used to contribute to structural imaging of a highly heterogeneous lava dome and to detect abrupt transient hydrothermal phenomena likely to produce dangerous explosive events.

Published
2022
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20. The thermal properties of hydrothermally altered andesites from La Soufrière de Guadeloupe (Eastern Caribbean)

Author

Michael J. Heap, David E. Jessop, Fabian B. Wadsworth, Marina Rosas-Carbajal, Jean-Christophe Komorowski, H. Albert Gilg, Nadège Aron, Margaux Buscetti, Laura Gential, Margaux Goupil, Mathilde Masson, Lucie Hervieu, Alexandra R.L. Kushnir, Patrick Baud, Lucille Carbillet, Amy G. Ryan, Roberto Moretti, Ecole et Observatoire des Sciences de la Terre (EOST), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), 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), Department of Earth, Ocean and Atmospheric Sciences [Vancouver] (UBC EOAS), University of British Columbia (UBC), Heap, M. J., Jessop, D. E., Wadsworth, F. B., Rosas-Carbajal, M., Komorowski, J. -C., Gilg, H. A., Aron, N., Buscetti, M., Gential, L., Goupil, M., Masson, M., Hervieu, L., Kushnir, A. R. L., Baud, P., Carbillet, L., Ryan, A. G., Moretti, R., Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), 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), Durham University, Engineering Geology, TUM School of Engineering and Design, Technical University of Munich, Department of Earth and Environmental Sciences, University of Minnesota, and ANR-21-CE49-0010,MYGALE,Modélisation phYsico-chimique des Gradients de l'ALtération hydrothermale: sentinelle de la dynamique d'instabilité gravitaire des volcans Explosifs(2021)

Subjects
010504 meteorology & atmospheric sciences, Merapi, 010502 geochemistry & geophysics, 01 natural sciences, Specific heat capacity, Thermal diffusivity, Chaos Crags, Geophysics, 13. Climate action, Geochemistry and Petrology, Thermal conductivity, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Chaos Crag, Heat flux, Alteration, Porosity, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience; The heat flux of an active volcano provides crucial information on volcanic unrest. The hydrothermal activity often responsible for volcanic unrest can be accompanied by an increase in the extent and intensity of hydrothermal alteration, which could influence the thermal properties of the volcanic edifice. Therefore, an understanding of the influence of alteration on the thermal properties of rocks is required to better interpret volcano heat flux data. We provide laboratory measurements of thermal conductivity, thermal diffusivity, and specific heat capacity for variably altered (intermediate to advanced argillic alteration) andesites from La Soufrière de Guadeloupe (Eastern Caribbean). We complement these data with previously published data for altered basaltic-andesites from Merapi (Indonesia) and new data for altered rhyodacites from Chaos Crags (USA). Our data show that thermal conductivity and thermal diffusivity decrease as a function of increasing porosity, whereas the specific heat capacity does not change systematically. Thermal conductivity decreases as a function of alteration (the percentage of secondary minerals) for the rocks from La Soufrière and Merapi (from ~1.6 to ~0.6 W·m−1·K−1 as alteration increases from ~1.5 to >75 wt%), but increases for the rocks from Chaos Crags (from ~1.1 to ~1.5 W·m−1·K−1 as alteration increases from ~6 to ~15 wt%). Although the thermal diffusivity of the rocks from Chaos Crags increases from ~0.65 to ~0.75–0.95 mm2·s−1 as alteration increases from ~6 to ~15 wt%, the thermal diffusivity of the rocks from La Soufrière and Merapi does not appear to be greatly influenced by alteration. The specific heat capacity is not significantly affected by alteration, although there is a slight trend of increasing specific heat capacity with alteration for the rocks from La Soufrière. We conclude that the decrease in thermal conductivity as a function of alteration in the rocks from La Soufrière and Merapi is the result of the low conductivity of the secondary mineral assemblage, and that a combination of the high thermal conductivity of cristobalite and the reduction in porosity as a result of the void-filling mineral precipitation can explain the increase in thermal conductivity in the rocks from Chaos Crags. Calculations show that an increase in alteration of a dome or edifice can result in decreases and increases in heat flow density, depending on the type of alteration. Therefore, alteration-induced changes in the thermal properties of dome or edifice rocks should be considered when interpreting volcano heat flux data. We conclude that it is important not only to monitor the extent and evolution of alteration at active volcanoes, but also the spatial distribution of alteration type.

Published
2021
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21. A multi-decadal view of the heat and mass budget of a volcano in unrest: La Soufrière de Guadeloupe (French West Indies)

Author

Jean-Christophe Komorowski, Alexis Bosson, David Jessop, Roberto Moretti, Séverine Moune, Dominique Gibert, Michael J. Heap, Vincent Robert, Sébastien Deroussi, Arnaud Lemarchand, Marina Rosas-Carbajal, Magali Bonifacie, Arnaud Burtin, Céline Dessert, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Observatoire Volcanologique et Sismologique de Guadeloupe (OVSG), Institut de Physique du Globe de Paris (IPG Paris), 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), 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), Institut de physique du globe de Strasbourg (IPGS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), ANR-18-IDEX-0001,Université de Paris,Université de Paris(2018), ANR-08-RISK-0002,DOMOSCAN,Quantification de la dynamique et suivi spatio-temporelle du système hydrothermal de la Soufrière de Guadeloupe(2008), ANR-14-CE04-0001,DIAPHANE,Imageries structurelle et fonctionnelle de volcans avec des rayons cosmiques(2014), Institut de Physique du Globe de Paris, 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), 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), Jessop, D. E., Moune, S., Moretti, R., Gibert, D., Komorowski, J. -C., Robert, V., Heap, M. J., Bosson, A., Bonifacie, M., Deroussi, S., Dessert, C., Rosas-Carbajal, M., Lemarchand, A., Burtin, A., Université Clermont Auvergne [2017-2020] (UCA [2017-2020]), Géosciences Rennes (GR), Université de Rennes 1 (UR1), 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), Géophysique expérimentale (IPGS) (IPGS-GE), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Dome, Pitot tube, Heat and mass flux, FOS: Physical sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], MultiGAS, 010502 geochemistry & geophysics, Atmospheric sciences, fumarole, 01 natural sciences, Hydrothermal circulation, Physics - Geophysics, Geochemistry and Petrology, Spring (hydrology), [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Sedimentology, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Unrest, Fumarole, Geophysics (physics.geo-ph), Volcano, Heat flux, 13. Climate action, [SDU]Sciences of the Universe [physics], Geology, airborne thermal imagery
Abstract

International audience; Particularly in the presence of a hydrothermal system, many volcanoes output large quantities of heat through the transport of water from deep within the edifice to the surface. Thus, heat flux is a prime tool for evaluating volcanic activity and unrest. We review the volcanic unrest at La Soufrière de Guadeloupe (French West Indies) using an airborne thermal camera survey and in situ measurements of temperature and flow rate through temperature probes, Pitot-tube and MultiGAS measurements. We deduce mass and heat fluxes for the fumarolic, ground and thermal spring outputs and follow these over a period spanning 2000–2020. Our results are compared with published data and we performed a retrospective analysis of the temporal variations in heat flux over this period using the literature data. We find that the heat emitted by the volcano is 36.5 ± 7.9MW, of which the fumarolic heat flux is dominant at 28.3 ± 6.8 MW. Given a total heated area of 26 270 m2, this equates to a total heat flux density of 1366 ± 82 W/m2, which is amongst the highest established for worldwide volcanoes with hydrothermal systems, particularly for dome volcanoes. A major change at La Soufrière de Guadeloupe, however, is the development of a widespread region of ground heating at the summit where heat output has increased from 0.2 ± 1 MW in 2010 to 5.7 ± 0.9 MW in 2020. This change is concurrent with accelerating unrest at the volcano and the emergence of two new high-flux fumaroles in recent years. Our findings highlight the importance of continued and enhanced surveillance and research strategies at La Soufrière de Guadeloupe, the results of which can be used to better understand hydrothermal volcanic systems the world over.

Published
2021
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22. Alteration-Induced Volcano Instability at La Soufrière de Guadeloupe (Eastern Caribbean)

Author

Jean-Christophe Komorowski, Marlene Villeneuve, Thierry Reuschlé, Tobias Baumann, Lucille Carbillet, Claire E. Harnett, Patrick Baud, Michael J. Heap, Marina Rosas-Carbajal, Roberto Moretti, H. Albert Gilg, Heap, M. J., Baumann, T. S., Rosas-Carbajal, M., Komorowski, J. -C., Gilg, H. A., Villeneuve, M., Moretti, R., Baud, P., Carbillet, L., Harnett, C., Reuschle, T., Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Geosciences [Mainz], Johannes Gutenberg - Universität Mainz (JGU), Institut de Physique du Globe de Paris, Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Montanuniversität Leoben (MUL), Observatoire Volcanologique et Sismologique de Guadeloupe (OVSG), University College Dublin [Dublin] (UCD), and Technical University of Munich (TUM)

Subjects
upscaling, Volcanic hazards, 010504 meteorology & atmospheric sciences, Young's modulus, Mass wasting, 010502 geochemistry & geophysics, 01 natural sciences, Instability, Hydrothermal circulation, Geochemistry and Petrology, Friction angle, Earth and Planetary Sciences (miscellaneous), Cohesion (geology), [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Argillic alteration, Petrology, hydrothermal alteration, uniaxial compressive strength, 0105 earth and related environmental sciences, flank collapse, geography, geography.geographical_feature_category, Geophysics, Volcano, 13. Climate action, Space and Planetary Science, Geology
Abstract

International audience; Volcanoes are unstable structures that deform laterally and frequently experience mass wasting events. Hydrothermal alteration is often invoked as a mechanism that contributes significantly to volcano instability. We present a study that combines laboratory experiments, geophysical data, and large-scale numerical modeling to better understand the influence of alteration on volcano stability, using La Soufrière de Guadeloupe (Eastern Caribbean) as a case study. Laboratory experiments on variably altered (advanced argillic alteration) blocks show that uniaxial compressive strength, Young's modulus, and cohesion decrease as a function of increasing alteration, but that the internal friction angle does not change systematically. Simplified volcano cross sections were prepared (a homogenous volcano, a volcano containing the alteration zone identified by a recent electrical survey, and a volcano with an artificially enlarged area of alteration) and mechanical properties were assigned to zones corresponding to unaltered and altered rock. Numerical modeling performed on these cross sections, using a hydro-thermo-mechanical modeling code, show (a) the importance of using upscaled values in large-scale models and (b) that alteration significantly increases volcano deformation and collapse volume. Finally, we combined published muon tomography data with our laboratory data to create a 3D strength map, exposing a low-strength zone beneath the southern flank of the volcano coincident with the hydrothermal system. We conclude that hydrothermal alteration decreases volcano stability and thus expedites volcano spreading and increases the likelihood of mass wasting events and associated volcanic hazards. Hydrothermal alteration, and its evolution, should therefore be monitored at active volcanoes worldwide.

Published
2021
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23. The 2018 unrest phase at La Soufrière of Guadeloupe (French West Indies) andesitic volcano: Scrutiny of a failed but prodromal phreatic eruption

Author

Jean-Marie Saurel, Thierry Kitou, Sébastien Deroussi, David Jessop, Arnaud Lemarchand, V. Robert, Nathalie Feuillet, P. Allard, Jean-Bernard de Chabalier, Giancarlo Tamburello, Martin Vallée, Dominique Gibert, Tara Shreve, François Beauducel, Roberto Moretti, Séverine Moune, Arnaud Burtin, Tristan Didier, Marina Rosas-Carbajal, Marc Chaussidon, G. Ucciani, Anne Le Friant, Pierre Agrinier, Magali Bonifacie, Jean-Christophe Komorowski, Observatoire Volcanologique et Sismologique de Guadeloupe (OVSG), Institut de Physique du Globe de Paris, Institut de Physique du Globe de Paris (IPGP), 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), Laboratoire Magmas et Volcans (LMV), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement et la société-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Université Jean Monnet [Saint-Étienne] (UJM), Géosciences Rennes (GR), 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), Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Bologna (INGV), Istituto Nazionale di Geofisica e Vulcanologia, Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique, Agence Nationale de la Recherche, Ministère de la Transition écologique et Solidaire, Precursory Research for Embryonic Science and Technology, Observatoires Volcanologiques et Sismologiques, Institut de Physique du Globe de Paris (IPG Paris), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), 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), ANR-18-IDEX-0001,Université de Paris,Université de Paris(2018), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), 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), Moretti, R., Komorowski, J. -C., Ucciani, G., Moune, S., Jessop, D., de Chabalier, J. -B., Beauducel, F., Bonifacie, M., Burtin, A., Vallee, M., Deroussi, S., Robert, V., Gibert, D., Didier, T., Kitou, T., Feuillet, N., Allard, P., Tamburello, G., Shreve, T., Saurel, J. -M., Lemarchand, A., Rosas-Carbajal, M., Agrinier, P., Le Friant, A., and Chaussidon, M.

Subjects
010504 meteorology & atmospheric sciences, 010502 geochemistry & geophysics, 01 natural sciences, Hydrothermal circulation, Hydrothermal system, Hydrothermal systems, Geochemistry and Petrology, Degassing, Hydrofracturing and hydroshearing, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Petrology, Volcanic unrest, Phreatic, 0105 earth and related environmental sciences, West indies, geography, geography.geographical_feature_category, Andesite, Unrest, Phreatic eruption, Geophysics, Volcano, 13. Climate action, Phreatic eruptions, Geology
Abstract

After 25 years of gradual increase, volcanic unrest at La Soufriere of Guadeloupe reached its highest seismic energy level on 27 April 2018, with the largest felt volcano-tectonic (VT) earthquake (M-L 4.1 or M-W 3.7) recorded since the 1976-1977 phreatic eruptive crisis. This event marked the onset of a seismic swarm (180 events, 2 felt) occurring after three previous swarms on 3-6 January (70 events), 1 st February (30 events, 1 felt) and 16-17 April (140 events, 1 felt). Many events were hybrid VI's with long-period codas, located 2-4 km below the volcano summit and clustered within 2 km along a regional NW-SE fault cross-cutting La Soufriere. Elastic energy release increased with each swarm whereas inter-event time shortened. At the same time, summit fractures continued to open and thermal anomalies to extend. Summit fumarolic activity increased significantly until 20 April, with a maximum temperature of 111.4 degrees C and gas exit velocity of 80 m/s, before declining to similar to 95 degrees C and similar to 33 m/s on 25 April. Gas compositions revealed increasing C/S and CO2/CH4 ratios and indicate hydrothermal P-T conditions that reached the critical point of pure water. Repeated MultiGAS analysis of fumarolic plumes showed increased CO2/H2S ratios and SO2 contents associated with the reactivation of degassing fractures (T = 93 degrees C, H2S/SO2 approximate to 1). While no direct evidence of upward magma migration was detected, we attribute the above phenomena to an increased supply of deep magmatic fluids that heated and pressurized the La Soufriere hydrothermal system, triggering seismogenic hydro-fracturing, and probable changes in deep hydraulic properties (permeability) and drainage pathways, which ultimately allowed the fumarolic fluxes to lower. Although this magmatic fluid injection was modulated by the hydrothermal system, the unprecedented seismic energy release and the critical point conditions of hydrothermal fluids suggest that the 2018 sequence of events can be regarded as a failed phreatic eruption. Should a similar sequence repeat, we warn that phreatic explosive activity could result from disruption of the shallow hydrothermal system that is currently responsible for 3-9 mm/y of nearly radial horizontal displacements within 1 km from the dome. Another potential hazard is partial collapse of the dome's SW flank, already affected by basal spreading above a detachment surface inherited from past collapses. Finally, the increased magmatic fluid supply evidenced by geochemical indicators in 2018 is compatible with magma replenishment of the 6-7 km deep crustal reservoir feeding La Soufriere and, therefore, with a potential evolution of the volcano's activity towards magmatic conditions.

Published
2020
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24. Spatio-Temporal Relationships between Fumarolic Activity, Hydrothermal Fluid Circulation and Geophysical Signals at an Arc Volcano in Degassing Unrest: La Soufrière of Guadeloupe (French West Indies)

Author

Allard, Deroussi, Kitou, Dessert, Bonifacie, Le Marchand, Moune, Didier, Moretti, Tamburello, Venugopal, DeChabalier, Rosas-Carbajal, Beauducel, Robert, Komorowski, Le Friant, Laboratoire Magmas et Volcans (LMV), 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), 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), 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), Institut de Physique du Globe de Paris, 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 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), Institut de Physique du Globe de Paris (IPG Paris), 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), Tamburello, G., Moune, S., Allard, P., Venugopal, S., Robert, V., Rosas-Carbajal, M., Deroussi, S., Kitou, G. -T., Didier, T., Komorowski, J. -C., Beauducel, F., De Chabalier, J. -B., Le Marchand, A., Le Friant, A., Bonifacie, M., Dessert, C., and Moretti, R.

Subjects
Hydrothermal ga, 010504 meteorology & atmospheric sciences, Dome, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, volcanic unrest, Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, Hydrothermal circulation, guadeloupe, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, 14. Life underwater, Electrical resistivity tomography, Petrology, 0105 earth and related environmental sciences, multigas, geography, geography.geographical_feature_category, Andesite, Volcanic ga, lcsh:QE1-996.5, Lava dome, la soufriere, Multiga, Unrest, extensometry, la soufrière, lcsh:Geology, hydrothermal gas, Volcano, 13. Climate action, General Earth and Planetary Sciences, volcanic gas
Abstract

： Over the past two decades, La Soufri&egrave, re volcano in Guadeloupe has displayed a growing degassing unrest whose actual source mechanism still remains unclear. Based on new measurements of the chemistry and mass flux of fumarolic gas emissions from the volcano, here we reveal spatio-temporal variations in the degassing features that closely relate to the 3D underground circulation of fumarolic fluids, as imaged by electrical resistivity tomography, and to geodetic-seismic signals recorded over the past two decades. Discrete monthly surveys of gas plumes from the various vents on La Soufri&egrave, re lava dome, performed with portable MultiGAS analyzers, reveal important differences in the chemical proportions and fluxes of H2O, CO2, H2S, SO2 and H2, which depend on the vent location with respect to the underground circulation of fluids. In particular, the main central vents, though directly connected to the volcano conduit and preferentially surveyed in past decades, display much higher CO2/SO2 and H2S/SO2 ratios than peripheral gas emissions, reflecting greater SO2 scrubbing in the boiling hydrothermal water at 80&ndash, 100 m depth. Gas fluxes demonstrate an increased bulk degassing of the volcano over the past 10 years, but also a recent spatial shift in fumarolic degassing intensity from the center of the lava dome towards its SE&ndash, NE sector and the Breislack fracture. Such a spatial shift is in agreement with both extensometric and seismic evidence of fault widening in this sector due to slow gravitational sliding of the southern dome sector. Our study thus provides an improved framework to monitor and interpret the evolution of gas emissions from La Soufri&egrave, re in the future and to better forecast hazards from this dangerous andesitic volcano.

Published
2019
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25. Modeling of partial dome collapse of La Soufrière of Guadeloupe volcano: implications for hazard assessment and monitoring.

Author

Peruzzetto M, Komorowski JC, Le Friant A, Rosas-Carbajal M, Mangeney A, and Legendre Y

Abstract

Over the past 9,150 years, at least 9 flank collapses have been identified in the history of La Soufrière of Guadeloupe volcano. On account of the volcano's current unrest, the possibility of such a flank collapse should not be dismissed in assessing hazards for future eruptive magmatic as well as non-magmatic scenarios. We combine morphological and geophysical data to identify seven unstable structures (volumes ranging from 1 × 10 6 m 3 to 100 × 10 6 m 3 ), including one that has a volume compatible with the last recorded flank collapse in 1530 CE. We model their dynamics and emplacement with the SHALTOP numerical model and a simple Coulomb friction law. The best-fit friction coefficient to reproduce the 1530 CE event is tan(7°) = 0.13, suggesting the transformation of the debris avalanche into a debris flow, which is confirmed by the texture of mapped deposits. Various friction angles are tested to investigate less water-rich and less mobile avalanches. The most densely populated areas of Saint-Claude and Basse-Terre, and an area of Gourbeyre south of the Palmiste ridge, are primarily exposed in the case of the more voluminous and mobile flank collapse scenarios considered. However, topography has a prominent role in controlling flow dynamics, with barrier effects and multiple channels. Classical mobility indicators, such as the Heim's ratio, are thus not adequate for a comprehensive hazard analysis.

Published
2019
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26. Volcano electrical tomography unveils edifice collapse hazard linked to hydrothermal system structure and dynamics.

Author

Rosas-Carbajal M, Komorowski JC, Nicollin F, and Gibert D

Abstract

Catastrophic collapses of the flanks of stratovolcanoes constitute a major hazard threatening numerous lives in many countries. Although many such collapses occurred following the ascent of magma to the surface, many are not associated with magmatic reawakening but are triggered by a combination of forcing agents such as pore-fluid pressurization and/or mechanical weakening of the volcanic edifice often located above a low-strength detachment plane. The volume of altered rock available for collapse, the dynamics of the hydrothermal fluid reservoir and the geometry of incipient collapse failure planes are key parameters for edifice stability analysis and modelling that remain essentially hidden to current volcano monitoring techniques. Here we derive a high-resolution, three-dimensional electrical conductivity model of the La Soufrière de Guadeloupe volcano from extensive electrical tomography data. We identify several highly conductive regions in the lava dome that are associated to fluid saturated host-rock and preferential flow of highly acid hot fluids within the dome. We interpret this model together with the existing wealth of geological and geochemical data on the volcano to demonstrate the influence of the hydrothermal system dynamics on the hazards associated to collapse-prone altered volcanic edifices.

Published
2016
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