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38 results on '"Courboulex, F."'

1. Modeling the Onset of Earthquake‐Triggered Landslides on Slip Surfaces Governed by Rate‐And‐State Friction.

Author

Lestrelin, H., Ampuero, J. P., Mercerat, E. D., and Courboulex, F.

Subjects
CYCLIC fatigue, TRAVEL time (Traffic engineering), THEORY of wave motion, SLOPE stability, EARTHQUAKES
Abstract

Earthquake‐triggered landslides are a severe hazard and contribute to landscape evolution. To understand their process and controlling factors, we model the onset of seismically‐triggered slip on pre‐existing slip surfaces governed by laboratory‐based rate‐and‐state friction, including wave propagation effects. Through numerical simulations and theoretical analysis, we identify how friction properties, landslide thickness and incident wave attributes (frequency, duration, amplitude) control slope stability. We find that the frictional state variable tracks the cyclic fatigue of the slip surface, its progressive weakening with each wave cycle. Wave propagation effects introduce two regimes depending on frequency relative to the two‐way travel time across the landslide thickness: the stability criterion is well approximated by a threshold on incident peak acceleration at low frequencies, and on peak velocity at high frequencies. We derive analytical approximations, validated by simulations, suitable to apply the model to evaluate landslide stability under arbitrary input motions. Plain Language Summary: Landslides induced by earthquake shaking cause human and economic losses. Understanding their triggering mechanism is a key to reduce their impact. Here we propose a new model for the onset of seismically‐triggered landslide slip using a friction law based on laboratory experiments. Studying the model mathematically and through computer simulations, we identify the specific attributes of the landslide and incident seismic waves that control slope stability. We find that the decrease of the frictional state variable is a good proxy for the approach to instability. The landslide triggering criterion is well described by a peak acceleration threshold if the landslide is shallow or the earthquake shaking is dominated by low frequencies, and by a peak velocity threshold for deep landslides or high‐frequency shaking. Finally, we develop equations that can be used to assess landslide stability to shaking without the need for computer simulations. Key Points: Numerical and analytical modeling of earthquake‐induced landslides on slip surfaces governed by rate‐and‐state frictionThe frictional state variable tracks the landslide fatigue manifested by progressive weakening of the slip surfaceLandslide triggering by low‐ and high‐frequency shaking is controlled by peak acceleration and velocity, respectively [ABSTRACT FROM AUTHOR]

Published
2024
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6. Citizen seismology helps decipher the 2021 Haiti earthquake.

Author

Calais, E., Symithe, S., Monfret, T., Delouis, B., Lomax, A., Courboulex, F., Ampuero, J. P., Lara, P. E., Bletery, Q., Chèze, J., Peix, F., Deschamps, A., de Lépinay, B., Raimbault, B., Jolivet, R., Paul, S., St Fleur, S., Boisson, D., Fukushima, Y., and Duputel, Z.

Published
2022
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7. Profiling the Quito basin (Ecuador) using seismic ambient noise.

Author

Pacheco, D, Mercerat, E D, Courboulex, F, Bonilla, L F, Laurendeau, A, and Alvarado, A

Subjects
SURFACE waves (Seismic waves), MICROSEISMS, WAVE amplification, GREEN'S functions, RAYLEIGH waves, SEISMIC waves, ADAKITE, FAULT zones
Abstract

Quito, the capital of Ecuador, with more than 2.5 M inhabitants, is exposed to a high seismic hazard due to its proximity to the Pacific subduction zone and active crustal faults, both capable of generating significant earthquakes. Furthermore, the city is located in an intermontane piggy-back basin prone to seismic wave amplification. To understand the basin's seismic response and characterize its geological structure, 20 broad and medium frequency band seismic stations were deployed in Quito's urban area between May 2016 and July 2018 that continuously recorded ambient seismic noise. We first compute horizontal-to-vertical spectral ratios to determine the resonant frequency distribution in the entire basin. Secondly, we cross-correlate seismic stations operating simultaneously to retrieve interstations surface-wave Green's functions in the frequency range of 0.1–2 Hz. We find that Love waves travelling in the basin's longitudinal direction (NNE–SSW) show much clearer correlograms than those from Rayleigh waves. We then compute Love wave phase-velocity dispersion curves and invert them in conjunction with the HVSR curves to obtain shear-wave velocity profiles throughout the city. The inversions highlight a clear difference in the basin's structure between its northern and southern parts. In the centre and northern areas, the estimated basin depth and mean shear-wave velocity are about 200 m and 1800 ms−1, respectively, showing resonance frequency values between 0.6 and 0.7 Hz. On the contrary, the basement's depth and shear-wave velocity in the southern part are about 900 m and 2500 ms−1, having a low resonance frequency value of around 0.3 Hz. This difference in structure between the centre-north and the south of the basin explains the spatial distribution of low-frequency seismic amplifications observed during the M w 7.8 Pedernales earthquake in April 2016 in Quito. [ABSTRACT FROM AUTHOR]

Published
2022
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8. The Ms = 6.2, June 15, 1995 Aigion earthquake (Greece): evidence for low angle normal faulting in the Corinth rift

Author

Bernard, P., Briole, P., Meyer, B., Lyon-Caen, H., Gomez, J.-M., Tiberi, C., Berge, C., Cattin, R., Hatzfeld, D., Lachet, C., Lebrun, B., Deschamps, A., Courboulex, F., Larroque, C., Rigo, A., Massonnet, D., Papadimitriou, P., Kassaras, J., Diagourtas, D., Makropoulos, K., Veis, G., Papazisi, E., Mitsakaki, C., Karakostas, V., Papadimitriou, E., Papanastassiou, D., Chouliaras, M., and Stavrakakis, G.

Published
1997
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10. Seismic interferometry at the urban scale: imaging the Quito basin

Author

daniel, pacheco, Mercerat, Diego, Courboulex, F., Laurendeau, Aurore, Alvarado, Alexandra, 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), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet MOUVGS (Cerema Equipe-projet MOUVGS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Instituto Geofísico (IG), Escuela Politécnica Nacional del Ecuador, Instituto Geofísico, Escuela Politécnica Nacional, Escuela Politécnica Nacional, ANR-15-CE04-0004,REMAKE,Risque sismique en Equateur: réduction, anticipation, connaissance des séismes(2015), 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]), Escuela Politécnica Nacional (EPN), Courboulex, Françoise, Risque sismique en Equateur: réduction, anticipation, connaissance des séismes - - REMAKE2015 - ANR-15-CE04-0004 - AAPG2015 - VALID, and 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])

Subjects
south america, urban risk, Seismic Hazar, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; Temporary seismic networks installed in urban areas provide a powerful tool for investigating the shal-low geological structure and assess the seismic hazard using seismic interferometry. Quito, the capital of Ecuador, is located in a high seismic zone, placed at 200 km from the Pacific sub-duction zone and surrounded by crustal-faults prone to generate significant earthquakes. The city has been built on a basin, on the hanging wall of a system of active reverse faults. The high population density (around 3 million inhabitants), together with the lack of planning in most of its buildings, make Quito a metropolis with a high seismic risk. In Quito, the filling of the basin has been described as volcano-sedimentary sequences consisting of lavas, lahars, lacustrine and pyroclastic deposits. However, the thickness of the in-fill material, its spa-tial arrangement, and the deep structure of the basin remain poorly known. Between May 2016 and July 2018, 20 broad- and mid-band seismological stations were deployed pro-gressively throughout the city in an irregular array to record ambient seismic noise to investigate the upper-most geological structure of the basin. Here, we present the results of ambient noise cross-correlations of simultaneous operating seismic stations to retrieve inter-stations surface waves Green's functions in the frequency band 0.1 - 2 Hz. Careful analyses of day-night variations in noise spectral power have been done to select optimal time windows for the cross-correlations. Rayleigh and Love phase- velocity dispersion curves were inverted to obtain shear wave velocity profiles throughout the city. Love wave trains traveling in the longitudinal direction of the basin (NNE-SSW) are much clearer than Rayleigh wave trains. The surface waves Green’s functions and their inversions mark a clear difference in the structure of the basin between the northern and southern parts. At the north, we detect the seismic basement at a depth of about 500 meters whereas at the south it appears much deeper around 1300 meters. This strong difference could be the main explanation for the low-frequency amplification (at 0.3 Hz) highlighted in the southern part of the basin on the recording of earthquakes (the April 2016, Mw 7.8 Pedernales earthquake being an example) and by the analysis of spectral ratios (Laurendeau et al., 2017).

Published
2019

11. Are subduction earthquakes a threat for Quito, capital of Ecuador, located ~170 km from the coast?

Author

Courboulex, F., Castro Cruz, David Alejandro, Laurendeau, Aurore, Alvarado, Alexandra, Bonilla, Luis Fabian, Bertrand, Etienne, Mercerat, Diego, 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]), Instituto Geofísico (IG), Escuela Politécnica Nacional del Ecuador, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Séismes et Vibrations (IFSTTAR/GERS/SV), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Communauté Université Paris-Est, Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet MOUVGS (Cerema Equipe-projet MOUVGS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), ANR-15-CE04-0004,REMAKE,Risque sismique en Equateur: réduction, anticipation, connaissance des séismes(2015), 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]), Communauté Université Paris-Est-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 [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)

Subjects
South america, Ground motion simulations, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Quito risk, [SPI.GCIV.RISQ]Engineering Sciences [physics]/Civil Engineering/Risques, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Seismology Earthquake source observations 1240, Seismic hazards
Abstract

International audience; The city of Quito (3M inhabitants), capital of Ecuador, is prone to seismic hazard and the associated risk is increasing due to its growing. The city has been damaged several times in the past by earthquakes that occurred on crustal faults around Quito or in the Cordillera (Beauval et al., 2010). As far as we know, the earthquakes that occurred along the subduction’s interface have never strongly damaged Quito: such as the recent Pedernales earthquake (Mw 7.8, 2016) and also the largest known earthquake of Ecuador, the Esmeraldas earthquake (Mw> 8.4, 1906). Nevertheless, can we be certain that very large subduction earthquakes could not treat the city of Quito (which extension is much larger than in 1906)? This question is particularly important since the recent discovery of a clear site effect in the southern part of the city that amplifies seismic waves (Laurendeau et al., 2017) at low frequencies (around 0.3Hz) and the future urban planning that considers high-rise buildings due to the saturation of usable land in the valley.In order to investigate this question, we propose a simple method for estimating reliable values of ground motions due to a future earthquake and its variability. The method is based on a scheme of summation of small earthquakes used as empirical Green’s functions, combined with constraints given by a global data base of STF (source time functions, SCARDEC database, Vallée et al., 2013). In this approach we use the mean value and the variability of the STF duration obtained in subduction domains (Courboulex et al, 2016) as constraints for the source variability. Indeed, STF duration naturally includes the effects of stress-drop, rupture velocity and it is independent of the source model. In a first step, we test and validate the approach by simulating the ground motions in Quito generated by a Mw 7.8 earthquake, similar to the Pedernales earthquake that occurred on April 16th 2016 along the subduction zone. This event and its largest aftershocks have been well recorded by 18 permanent accelerometric stations (RENAC network) and then allowed us to compare the blind simulation and the Pedernales data. The good results obtained pushed us to simulate a larger earthquake, M=8.5 in the same zone. We considered 4 different simple scenarios with one to three sub-events and a propagation of the rupture towards the south and towards the north. At high frequencies (PGA), the values obtained are not very high (PGA < 0.2g) and are comparable to the predictions using Abrahamson et al. (2016) ground motion prediction equations. However, at lower frequencies, the ground motion values are much stronger than expected, especially in the south of the basin. These results could be taken into account in the building codes to avoid possible future destructions of infrastructures that may resonate at these low frequencies.References : Beauval, C., Yepes, et al. (2010). Locations and magnitudes of historical earthquakes in the Sierra of Ecuador (1587–1996). GJI. / Courboulex, et al. (2016). Stress drop variability of shallow earthquakes extracted from a global database of STF. SRL/ Laurendeau, et al. (2017). Low‐Frequency Seismic Amplification in the Quito Basin (Ecuador), BSSA, /Vallée, M. (2013). Source time function properties... Nat. Com.

Published
2019

12. Imaging the Quito basin using ambient seismic noise

Author

daniel, pacheco, Mercerat, Diego, Courboulex, F., Laurendeau, Aurore, Alvarado, Alexandra, 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]), Instituto Geofísico (IG), Escuela Politécnica Nacional del Ecuador, Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet MOUVGS (Cerema Equipe-projet MOUVGS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Instituto Geofísico, Escuela Politécnica Nacional, Escuela Politécnica Nacional (EPN), ANR-15-CE04-0004,REMAKE,Risque sismique en Equateur: réduction, anticipation, connaissance des séismes(2015), 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), Escuela Politécnica Nacional, and 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])

Subjects
south america, Seismic Noise, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, seismology, Seismic hazards, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

13. Apport des enregistrements sismologiques dans la prédiction du comportement non-linéaire des sols sous sollicitation sismique

Author

Castro Cruz, David Alejandro, Bertrand, Etienne, Julie, Régnier, Courboulex, F., Courboulex, Françoise, 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]), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet MOUVGS (Cerema Equipe-projet MOUVGS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), 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), and 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])

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

International audience

Published
2019

14. Impact of seismicity on Nice slope stability

Author

Roesner, A., Wiemer, G., Kreiter, S., Wenau, S., Wu, T.-W., Courboulex, F., Spiess, V., Kopf, A., and Publica

Abstract

The shallow Nice submarine slope is notorious for the 1979 tsunamigenic landslide that caused eight casualties and severe infrastructural damage. Many previous studies have tackled the question whether earthquake shaking would lead to slope failure and a repetition of the deadly scenario in the region. The answers are controversial. In this study, we assess for the first time the factor of safety using peak ground accelerations (PGAs) from synthetic accelerograms from a simulated offshore Mw 6.3 earthquake at a distance of 25 km from the slope. Based on cone penetration tests (CPTu) and multichannel seismic reflection data, a coarser grained sediment layer was identified. In an innovative geotechnical approach based on uniform cyclic and arbitrary triaxial loading tests, we show that the sandy silt on the Nice submarine slope will fail under certain ground motion conditions. The uniform cyclic triaxial tests indicate that liquefaction failure is likely to occur in Nice slope sediments in the case of a Mw 6.3 earthquake 25 km away. A potential future submarine landslide could have a slide volume (7.7 × 106 m3) similar to the 1979 event. Arbitrary loading tests reveal post-loading pore water pressure rise, which might explain post-earthquake slope failures observed in the field. This study shows that some of the earlier studies offshore Nice may have overestimated the slope stability because they underestimated potential PGAs on the shallow marine slope deposits.

Published
2019

15. Monitoring Haiti's quakes with raspberry shake

Author

Calais, E., Boisson, D., Symithe, S., Momplaisir, R., Prépetit, C., Ulysse, S., Etienne, G.P., Courboulex, F., Deschamps, A., Monfret, T., Ampuero, Jean-Paul, Mercier de Lépinay, B., Clouard, V., Bossu, R., Fallou, L., and Bertrand, E.

Abstract

A network of "personal seismometers" is intended to complement Haiti's national seismic network to engage and inform residents about earthquake hazards and preparation.

Published
2019

16. Seismic and landslides hazards in the high stakes area of the Nice Côte d'Azur airport

Author

Courboulex, F., Sébastien Migeon, Anthony Sladen, Christophe Larroque, Maëlle Kelner, Anne Deschamps, Yann Hello, Courboulex, Françoise, Idex UCA JEDI - - UCA JEDI2015 - ANR-15-IDEX-0001 - IDEX - VALID, Suivi temporel de déformation et évaluation des aléas gravitaires associés à des pressions de fluide (pente niçoise). - - MODAL2017 - ANR-17-CE01-0017 - AAPG2017 - VALID, Géoazur (GEOAZUR 7329), 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)-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]), Sorbonne Université (SU), Université de Reims Champagne-Ardenne (URCA), ANR-15-IDEX-0001,UCA JEDI,Idex UCA JEDI(2015), ANR-17-CE01-0017,MODAL,Suivi temporel de déformation et évaluation des aléas gravitaires associés à des pressions de fluide (pente niçoise).(2017), 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]), ANR: 15-IDEX-0001,UCA JEDI,Idex UCA JEDI(2015), 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), and 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])

Subjects
[SHS.SOCIO]Humanities and Social Sciences/Sociology, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SHS.SOCIO] Humanities and Social Sciences/Sociology, [SPI] Engineering Sciences [physics], offshore landslides, [SHS.GEO] Humanities and Social Sciences/Geography, Landslides-prone areas, Site effects, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SHS.GEO]Humanities and Social Sciences/Geography, [SDE.ES]Environmental Sciences/Environmental and Society, Seismic hazards, [SPI]Engineering Sciences [physics], [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU.GP] Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.ES] Environmental Sciences/Environmental and Society
Abstract

International audience; A smart city must be equipped with efficient and interconnected transportation. Unfortunately, economic or operational reasons for creating an infrastructure sometimes compete with imperatives of natural hazards. The case of Nice Cote d'Azur airport is an interesting example. As air traffic increased, the airport has been progressively extended. The largest extension occurred between 1975 and 1979 when a large amount of backfill material has been accumulated on the continental shelf to reclaim land and create new tracks. In October 1979, a submarine landslide destroyed part of a seawall under construction and killed 10 people. This landslide was associated with a tsunami wave that swept the coast from Menton to Antibes: the damage was significant but much less than if it had occurred in summer during the tourist season. This disaster stopped all projects in the area for 40 years. However, recently, development projects have again been mentioned (information relayed by the press) with, in particular, the idea of a new port near the airport, able to accommodate ferries.For several years now, scientists have been working on the area to qualify natural hazard. Their results show that the airport tracks are subsiding [1] and that the surrounding offshore area is subject to recurrent small landslides [2], while geotechnical studies point to its unstable nature [3]. Recently, a seismological sensor installed under the sea during two years has recorded small local earthquakes. Our analysis of the signals revels a strong amplification effect of seismic waves related with the presence of a thick layer of sediments. Likewise, a future larger earthquake would also be amplified in this area, accentuating the potential for a significant submarine landslide. A domino effect is therefore to be feared: an earthquake, a landslide, a tsunami and maybe the only major local airport unable to operate properly in a time of crisis.A smart city should be a safe and resilient city that takes into account the contributions of all its stakeholders, including scientists. How scientific results can be taken into account into public decisions is still an open question.[1] Cavalié O., Sladen A., & Kelner M. (2015) Natural Hazards and Earth System Sciences [2] Kelner M., Migeon S. et al. (2016) Marine Geology [3] Dan G., Sultan et al. (2007) Marine Geology.

Published
2019

17. Seismic Response of the Quito Basin (Ecuador)

Author

Courboulex, F., Diego Mercerat, E., Laurendeau, Aurore, Alvarado, Alexandra, daniel, pacheco, Maria, Reyes, Gueguen, Philippe, Bertrand, Etienne, Juan, Barros, Matthieu, Perrault, Singaucho, Juan Carlos, 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]), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet MOUVGS (Cerema Equipe-projet MOUVGS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Instituto Geofísico, Escuela Politécnica Nacional, Escuela Politécnica Nacional (EPN), 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)-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), Escuela Politécnica Nacional, 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), ANR-15-CE04-0004,REMAKE,Risque sismique en Equateur: réduction, anticipation, connaissance des séismes(2015), and 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])

Subjects
RISQUE MAJEUR, CATASTROPHE NATURELLE, ECUADOR, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, SISMOLOGIE, EARTHQUAKE, SITE EFFECTS, EQUATEUR, ComputingMilieux_MISCELLANEOUS
Abstract

ESC, the 36th General Assembly of the European Seismological Commission, La Valette, MALTE, 02-/09/2018 - 07/09/2018

Published
2018

18. Quantified sensitivity of small lake sediments to record historic earthquakes: Implications for paleoseismology

Author

Wilhem , B., Nomade , J., Crouzet , Ch., Litty , C., Sabatier , P., Belle , S., Rolland , Y., Revel , Michel, Courboulex , F., Arnaud , F., Anselmetti , F. S., Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), 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]), 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), Géoazur (GEOAZUR 7329), 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, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Geological Institute [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire d'étude des transferts en hydrologie et environnement ( LTHE ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National Polytechnique de Grenoble ( INPG ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -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 ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Oeschger Centre for Climate Change Research ( OCCR ), University of Bern, 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 ), Institute of Geological Sciences, Environnements, Dynamiques et Territoires de la Montagne ( EDYTEM ), Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), 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 ), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), 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 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]), Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Laboratoire Chrono-environnement (UMR 6249) (LCE), 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), 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), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), 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), Department of Earth Sciences [ETH Zürich] (D-ERDW), and Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)

Subjects
[SDE.IE]Environmental Sciences/Environmental Engineering, [SDE.MCG]Environmental Sciences/Global Changes, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, [SHS.GEO]Humanities and Social Sciences/Geography, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDE.ES]Environmental Sciences/Environmental and Society, 550 Earth sciences & geology
Abstract

International audience; Seismic hazard assessment is a critical but challenging issue for modern societies. A key parameter to be estimated is the recurrence interval of damaging earthquakes. This requires the establishment of earthquake records long enough to be relevant, i.e., far longer than historical observations. We study how lake sediments can be used for this purpose and explore conditions that enable lake sediments to record earthquakes. This was achieved (i) through the compilation of eight lake-sediment sequences from the European Alps to reconstruct chronicles of mass movement deposits and (ii) through the comparison of these chronicles with the well-documented earthquake history. This allowed 24 occurrences of mass movements to be identified, of which 21 were most probably triggered by an earthquake. However, the number of earthquake-induced deposits varies between lakes of a same region, suggesting variable thresholds of the lake sequences to record earthquake shaking. These thresholds have been quantified by linking the mass movement occurrences in a single lake to both intensity and distance of the triggering earthquakes. This method offers a quantitative approach to estimate locations and intensities of past earthquake epicenters. Finally, we explored which lake characteristics could explain the various sensitivities. Our results suggest that sedimentation rate should be larger than 0.5 mm yr−1 so that a given lake records earthquakes in moderately active seismotectonic regions. We also postulate that an increasing sedimentation rate may imply an increasing sensitivity to earthquake shaking. Hence, further paleoseismological studies should control carefully that no significant change in sedimentation rates occurs within a record, which could falsify the assessment of earthquake recurrence intervals.

Published
2016
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19. Sismos à l'Ecole: A Worldwide Network of Real‐Time Seismometers in Schools

Author

Courboulex, F., Bérenguer, Jean-Luc, Tocheport, A., Bouin, M.P., Calais, E., Esnault, Y., Larroque, Christophe, Nolet, Guust, Virieux, Jean, Géoazur (GEOAZUR 6526), 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)-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), Observatoire Volcanologique de Guadeloupe, Department of Earth and Atmospheric Sciences [West Lafayette], Purdue University [West Lafayette], sciences à l'école, Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), 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), 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)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-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]), and Géoazur, Publications

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

International audience; After each large destructive earthquake in the world, shocking images are presented to the adults and children on the TV and through the Internet. All sorts of questions arise: Some of them are very rational, whereas others are driven by fear of a global catastrophe or even a curse. For example, in March 2011, after the giant Tohoku, Japan, earthquake, seismologists everywhere were asked to provide explanations and often to give their opinion on what had happened. How could there be such a disaster? Can it happen to us? Many took the time to talk to students in classrooms to make clear what we know and what we are still trying to understand and also tried to limit irrational fears. Teachers, as well as researchers, were on the front line, particularly those who actively participate in networks of educational seismology in the United States (e.g., Levy and Taber, 2005), England (e.g., Denton, 2009), Italy (e.g., Cantore et al., 2003; Solarino and Eva, 2009), Switzerland (e.g., Sornette and Haslinger, 2009), and other countries in the world. Thanks to Sismos à l'Ecole (SaE) network stations, accessible in real time in various parts of the world, students saw the waves of the many aftershocks passing through their school and through other schools in the world. Thus, they immediately understood that the waves of Japanese earthquakes first arrived at the high school stations in Taipei, then in Canberra, and then in Istanbul before arriving under their feet at their school. Let us see how this network is structured and how it allows ...

Published
2012

20. Rapid response to the earthquake emergency of May 2012 in the Po Plain, northern Italy

Author

Moretti, Milena, Abruzzese, L., Abu Zeid, N., Courboulex, F., Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Roma (INGV), Istituto Nazionale di Geofisica e Vulcanologia, Université de Ferrara, Géoazur (GEOAZUR 6526), 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)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), and COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

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

International audience; Rapid-response seismic networks are an important element in the response to seismic crises. They temporarily improve the detection performance of permanent monitoring systems during seismic sequences. The improvement in earthquake detection and location capabilities can be important for decision makers to assess the current situation, and can provide invaluable data for scientific studies related to hazard, tectonics and earthquake physics. Aftershocks and the clustering of the locations of seismic events help to characterize the dimensions of the causative fault. Knowing the number, size and timing of the aftershocks or the clustering seismic events can help in the foreseeing of the characteristics of future seismic sequences in the same tectonic environment. Instrumental rapid response requires a high degree of preparedness. A mission in response to a magnitude (Ml) 6 event with a rupture length of a few tens of kilometers might involve the deployment within hours to days of 30-50 seismic stations in the middle of a disaster area of some hundreds of square kilometers, and the installation of an operational center to help in the logistics and communications. When an earthquake strikes in a populated area, which is almost always the case in Italy, driving the relevant seismic response is more difficult. […]

Published
2012
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21. Ground motion simulations of a major historical earthquake (1660) in the French Pyrenees using recent moderate size earthquakes

Author

Honoré, L., Courboulex, F., Souriau, A., Géoazur (GEOAZUR 6526), 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)-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), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), 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 -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), 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), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-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 (... - 2019) (UNS), 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 national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), and 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)

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

International audience; In regions where only small- to moderate-size events have been recorded, it is important to be able to anticipate the effects of a large event by simulating the ground motion it may generate. Using the very good records of two small earthquakes that occurred in the central French Pyrenees (2007 November 15, Mw= 3.6; and 2006 November 17, Mw= 4.5), we simulated the ground motions generated by a magnitude 6.1 earthquake, equivalent to a historical event that struck the region in 1660. This major earthquake caused severe damage and reached a maximum macroseismic intensity of IX on the MSK scale. The simulation is based on the empirical Green's function (EGF) method, which allows simulations in a broad frequency range, and accounts for both propagation and site effects. We first validated the method by reproducing the records of the Mw= 4.5 earthquake using the Mw= 3.6 earthquake as an EGF. A careful analysis of corner frequencies and spectral ratios revealed a clear directivity effect of the rupture process for the larger event (Mw= 4.5). When this directivity is taken into account in the simulation, a very good reproduction of the Mw= 4.5 ground motion parameters is obtained at all the stations. We then used the records of the Mw= 3.6 earthquake as an EGF for simulating the historical event. At 11 stations we computed a large number of synthetic accelerograms that aim to account for the possible source variability of an Mw= 6.1 earthquake. The comparison between the computed ground accelerations and those given by three different empirical ground motion prediction equations (GMPEs) reveals that simulation is quite successful. Finally, our simulation results are compared with intensity data of the 1660 event, by use of three different Ground Motion Intensity Conversion Equations (GMICEs). We found that the intensity levels predicted from ground motion simulations are systematically lower than the reported macroseismic intensities. To explain this difference, the hypothesis of a possible underestimation of the magnitude of the 1660 event is discussed.

Published
2011
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23. Feeling the Earth Shake ... at school. EDUSISMO : the French educational Seismological Network

Author

Bérenguer, J.L., Courboulex, F., Leputh, J., Zodmi, B., Bernard, P., Larroque, C., Matias, L., Moulié, F., Ngo, O., Nolet, G., Tartière, M., Tilquin, F., Virieux, J., Géoazur, Publications, 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, 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), Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Laboratoire Central des Ponts et Chaussées (LCPC)-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)-Centre National de la Recherche Scientifique (CNRS), 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), 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), 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 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)

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Published
2009

24. Seismic hazard on the French Riviera : new data, interpretation and simulations

Author

Courboulex, F., Larroque, C., Deschamps, Anne, Kohrs-Sansorny, C., Gélis, C., Got, J.-L., Charreau, J., Stéphan, J.-F., Béthoux, N., Virieux, J., Brunel, D., Maron, C., Duval, A.-M., Perez, J.-L., Mondielli, P., Géoazur (GEOAZUR 6526), 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)-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), 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), ERA 6 Risque sismique (ERA 6 Risque sismique - Equipe recherche associée au LCPC), Avant création Cerema, Direction environnement urbanisme et construction, Principauté de Monaco, Principauté de Monaco, 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), 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), 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), Laboratoire Central des Ponts et Chaussées (LCPC)-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)-Centre National de la Recherche Scientifique (CNRS), 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), and 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)

Subjects
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, seismotectonics, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], earthquake location, strong ground motion, fault tectonics, microseismicity, earthquake-source mechanism
Abstract

International audience; We present here a detailed analysis of a seismic data set recorded by a dense seismological network installed over 6 months in the southeast of France. This experiment was set-up at the boundary between the Ligurian basin and the southern subalpine thrust belt (the Nice arc), which is a complex tectonic region that undergoes low to moderate seismicity. We recorded more than 500 microearthquakes, among which 348 occurred exactly in the centre of the network during a very active seismic sequence that lasted mainly over 2 months. We performed an absolute location of all of the events and calculated the magnitudes. Then we applied a cross-correlation technique to gather similar events and to relocate relatively few of them. This method revealed a very clear alignment of 19 events in a direction N120° oblique to the N20° general trend of seismicity. Focal mechanisms were determined for the four largest events and composite solutions for 32 smaller ones. Both the alignments of the earthquakes and the focal solutions revealed that two oblique segments of the fault were activated during the crisis. The main segment (8 km long) that was oriented NNE with a left-lateral strike slip movement is called the Blausasc fault. Taking into account the tectonic evolution and the relationships between surface structures and the distribution of earthquakes, and through a paleaoreconstruction of the tectonic evolution, we propose that the Blausasc fault is the hidden root of the Peille-Laghet fault, which has a mapped length of at least 15 km. The smaller segment (0.6 km long) that was activated during the crisis could be interpreted as an antithetic Riedel fracture. The active Blausasc fault is located in a densely populated zone, at only 10 km from the crowded cities of Monaco and Nice. It is thus particularly interesting to analyse it for hazard assessment. In the last section, we present a simulation that is aimed at predicting what the ground motion in the city of Nice would be like if an earthquake of magnitude 5.7 occurs on this fault. For this, we used the recordings of the largest event of the seismic sequence (Ml= 3.2) and an empirical Green's function summation scheme to simulate the ground motion at two stations situated in urban environments. The values obtained show that especially on soft soil sites, the effects of such an earthquake would be considerable in the city of Nice.

Published
2007
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25. Transfert vers la société – Valorisation des recherches

Author

Anne-Marie Duval, Bertrand, E., Vidal, S., Y Bard, P., Guéguen, P., Courboulex, F., Davi, D., 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, and 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)

Abstract

Numéro spécial du BLPC sur les risques sismiques, 2007; International audience

Published
2007

26. Complex kinematic rupture of the Mw 5.9, 1999 Athens earthquake as revealed by the joint inversion of regional seismological and SAR data

Author

Baumont, D., Scotti, O., Courboulex, F., Melis, N., Géoazur (GEOAZUR 6526), 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), Bureau d'Evaluation des Risques Sismiques pour la Sûreté des Installations Nucléaires (IRSN/DEI/SARG/BERSSIN), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), 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)-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), DEI/SARG/BERSSIN - Bureau d'Evaluation des Risques Sismiques pour la Sûreté des Installations Nucléaires (IRSN), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), and 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)

Subjects
[SDU]Sciences of the Universe [physics]
Abstract

Geophysical Journal International, v. 158, n. 3, p. 1078-1087, 2004. http://dx.doi.org/10.1111/j.1365-246X.2004.02374.x; International audience; Slip distributions of the moderate magnitude (Mw 5.9), 1999 Athens earthquake, inverted from surface waves and interferometric Synthetic Aperture Radar (SAR) images, show very different characteristics. The robustness analysis proposed in this study, confirms the discrepancy between the well-constrained features of each individual solution. Irrespective of the hypotheses we made (data/modeling errors, slow deformation, post- or pre-seismic slip), the joint inversion of the two data sets led to a complex and heterogeneous rupture model. This model is characterized by a short rise time (

Published
2004
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27. An Unknown active fault revealed by microseismicity in the South-East of France

Author

Courboulex, F., Larroque, C., Deschamps, Anne, Gélis, C., Charreau, J., Stéphan, J.-F., 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, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), and 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)

Subjects
[SDU]Sciences of the Universe [physics]
Abstract

Geophysical Research Letters, v. 30, n. 15, p. 1782, 2003. http://dx.doi.org/10.1029/2003GL017171; International audience

Published
2003
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28. Slip distribution of the Mw 5,9, 1999 Athens earthquake inverted from regional seismological data

Author

Baumont, D., Courboulex, F., Scotti, O., Melis, N., Stavrakakis, G., Géoazur (GEOAZUR 6526), 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)-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), Bureau d'évaluation des risques sismiques pour la sûreté des installations nucléaires (IPSN/DPRE/SERGD/BERSSIN), Département de protection de l'environnement (IPSN/DPRE), Institut de Protection et Sûreté Nucléaire (IPSN)-Institut de Protection et Sûreté Nucléaire (IPSN), NOA-IG, Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), and 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)

Subjects
7255 Seismology: Surface waves and free oscillations, 7209 Seismology: Earthquake dynamics and mechanics, [SDU]Sciences of the Universe [physics], 7215 Seismology: Earthquake parameters
Abstract

Geophysical Research Letters, v. 29, n. 15, p. NIL302-NIL305 [425], 2002. http://dx.doi.org/10.1029/2001GL014261; International audience; We studied the kinematic rupture process of the moderate magnitude (Mw 5.9), 1999 Athens earthquake using broadband seismic recordings at regional distances. The Apparent Source Time Functions (ASTF), obtained by retrieving the wave propagation and site effects from the seismic recordings using an empirical Green's function method, indicate a rather complex rupture with a source directivity primarily pointing towards Athens. To further characterize the faulting, we inverted the ASTFs for the kinematic history of the rupture using a damped-least square inversion scheme with inequality constraints. The rupture extent is delimited by a 10 km along-strike ×20 km along-dip zone. The mean slip amplitude on the observed rupture area is equal to 25 cm. The slip concentrates in two elongated zones with amplitudes reaching locally 60 cm. The total rupture lasted between 5 and 6 s.

Published
2002
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29. A site effect study in the Verchiano valley during the 1997 Umbria-Marche (Central Italy) earthquakes

Author

Gaffet, Stéphane, Cultrera, G., Dietrich, M., Courboulex, F., Marra, G., Bouchon, M., Caserta, A., Cornou, C., Deschamps, Anne, Glot, J.-P., Guiguet, R., Géoazur (GEOAZUR 6526), 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)-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), Istituto Nazionale di Geofisica e Vulcanologia, 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), 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), 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), 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)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Central des Ponts et Chaussées (LCPC)-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)-Centre National de la Recherche Scientifique (CNRS), 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, and Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)

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

International audience; Strong site effects were observed during the two M W 5.7 and M W 6.0 main shocks of the Colfiorito seismic crisis which occured on September 26, 1997 in Umbria-Marche (Central Italy).The most obvious indications of these effects are the dramatic differences in damage shown by buildings of similar construction in neighboring villages.Such observations were specifically made in the Verchiano valley in the fault area, 15 km south of Colfiorito where the Verchiano village and the Colle and Camino hamlets were heavily damaged (MCS intensity IX-X) since the first main shock of 1997/09/26,while in contrast, the Curasci village located 2 km eastwards remains almost intact.In order to study the anomalous ground motion amplifications in this area, an array of 11, 3-components seismo- and accelero-meters was set up during the 1997/10/20-24 period, extending from the western side of the valley, up to the top of Mount San Salvatore, going accross the Colle and Curasci hamlets.During the experiment, 67 aftershocks enlightened the valley from the Colfiorito (10 km north) and the Sellano (6 km south) active swarms.Seismic refraction experiments were conducted at the same time in the 500 m wide, 1500 m long Verchiano valley in order to determine the thickness and main characteristics of the alluvial infilling.The main results are: (i) compared to the valley side ground motion, and for all the events, recordings in the central part of the valley (piana di Verchiano) show relative amplification of sim10 with a clear lengthening of the seismogram duration by a factor of sim2 – (ii) broad band relative amplification of sim6–8 is also clearly identified at the top of the Mount San Salvatore overhanging the valley – (iii) any of the site effect measurements done explains by itself the strongly contrasted damage observed at Colle and Curasci: i.e. the modification of the near-field radiation pattern by interaction with the free heterogeneous surface may have induced local shadow zones that saved Curasci.

Published
2000
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30. The Ms=6.2, June 15, 1995 Aigion earthquake (Greece): Evidence for low angle normal faulting in the Corinth rift

Author

Bernard, P. Briole, P. Meyer, B. Lyon-Caen, H. Gomez, J.-M. Tiberi, C. Berge, C. Cattin, R. Hatzfeld, D. Lachet, C. Lebrun, B. Deschamps, A. Courboulex, F. Larroque, C. Rigo, A. Massonnet, D. Papadimitriou, P. Kassaras, J. Diagourtas, D. Makropoulos, K. Veis, G. Papazisi, E. Mitsakaki, C. Karakostas, V. Papadimitriou, E. Papanastassiou, D. Chouliaras, M. Stavrakakis, G.

Abstract

We present the results of a multidisciplinary study of the Ms = 6.2, 1995, June 15, Aigion earthquake (Gulf of Corinth, Greece). In order to constrain the rupture geometry, we used all available data from seismology (local, regional and teleseismic records of the mainshock and of aftershocks), geodesy (GPS and SAR interferometry), and tectonics. Part of these data were obtained during a postseismic field study consisting of the surveying of 24 GPS points, the temporary installation of 20 digital seismometers, and a detailed field investigation for surface fault break. The Aigion fault was the only fault onland which showed detectable breaks (

Published
1997

32. Seismic hazard on the French Riviera: observations, interpretations and simulations.

Author

Courboulex, F., Larroque, C., Deschamps, A., Kohrs-Sansorny, C., Gélis, C., Got, J. L., Charreau, J., Stéphan, J. F., Béthoux, N., Virieux, J., Brunel, D., Maron, C., Duval, A. M., Perez, J-L., and Mondielli, P.

Subjects
*EARTHQUAKE hazard analysis, *SEISMOLOGY, *SEISMIC event location, *STRUCTURAL geology, *GEOLOGIC faults
Abstract

We present here a detailed analysis of a seismic data set recorded by a dense seismological network installed over 6 months in the southeast of France. This experiment was set-up at the boundary between the Ligurian basin and the southern subalpine thrust belt (the Nice arc), which is a complex tectonic region that undergoes low to moderate seismicity. We recorded more than 500 microearthquakes, among which 348 occurred exactly in the centre of the network during a very active seismic sequence that lasted mainly over 2 months. We performed an absolute location of all of the events and calculated the magnitudes. Then we applied a cross-correlation technique to gather similar events and to relocate relatively few of them. This method revealed a very clear alignment of 19 events in a direction N120° oblique to the N20° general trend of seismicity. Focal mechanisms were determined for the four largest events and composite solutions for 32 smaller ones. Both the alignments of the earthquakes and the focal solutions revealed that two oblique segments of the fault were activated during the crisis. The main segment (8 km long) that was oriented NNE with a left-lateral strike slip movement is called the Blausasc fault. Taking into account the tectonic evolution and the relationships between surface structures and the distribution of earthquakes, and through a paleaoreconstruction of the tectonic evolution, we propose that the Blausasc fault is the hidden root of the Peille-Laghet fault, which has a mapped length of at least 15 km. The smaller segment (0.6 km long) that was activated during the crisis could be interpreted as an antithetic Riedel fracture. The active Blausasc fault is located in a densely populated zone, at only 10 km from the crowded cities of Monaco and Nice. It is thus particularly interesting to analyse it for hazard assessment. In the last section, we present a simulation that is aimed at predicting what the ground motion in the city of Nice would be like if an earthquake of magnitude 5.7 occurs on this fault. For this, we used the recordings of the largest event of the seismic sequence ( Ml= 3.2) and an empirical Green's function summation scheme to simulate the ground motion at two stations situated in urban environments. The values obtained show that especially on soft soil sites, the effects of such an earthquake would be considerable in the city of Nice. [ABSTRACT FROM AUTHOR]

Published
2007
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33. Complex Normal Faulting in the Apennines Thrust-and-Fold Belt: The 1997 Seismic Sequence in Central Italy.

Author

Chiaraluce, L., Amato, A., Selvaggi, G., Di Bona, M., Piccinini, D., Deschamps, A., Margheriti, L., Courboulex, F., Ripepe, M., Cocco, M., and Chiarabba, C.

Subjects
EARTHQUAKES, EARTHQUAKE zones, PALEOSEISMOLOGY, SEISMIC waves
Abstract

A long sequence of moderate-magnitude earthquakes (5< M <6) struck central Italy in September and October 1997. At the end of the sequence a year later, the seismogenic area extends for about 60 km along the Apennines. The analysis of historical seismicity suggests that this seismic sequence filled a >700-year gap in this portion of the chain. Other historical sequences in the same area are characterized by prolonged seismic release on adjacent fault segments, probably due to the involvement of shallow and complex structures inherited by the compressive tectonics. The distribution of seismicity and the fault-plane solutions show that the extension in this region is accomplished by normal faults dipping at relatively low angles (∼40°) to the southwest. The focal mechanisms of the largest shocks reveal normal faulting with extension perpendicular to the Apenninic chain (northeast-southwest), consistently with the Quaternary tectonics of the internal sector of the northern Apennine belt and with previous earthquakes in adjacent regions. Three mainshocks occurred on distinct 5- to 10-km-long fault segments, adjacent and slightly offset between each other. High-quality aftershock locations show that seismicity is confined within the sedimentary Mesozoic cover in the upper 8 km of the crest and that most of the aftershocks are shallower than the largest shocks, which nucleated at ∼6-km depth. Faults evidenced by aftershock locations have a planar geometry and show increased complexity toward the surface. Most of the aftershock focal mechanisms are dominated by normal faulting. Several strike-slip events occurred at shallow depths, reactivating portions of pre-existing thrust planes that segment the normal fault system. The spatiotemporal evolution of seismicity shows a peculiar migration of hypocenters along the strike of the main faults with multiple ruptures and the activation of fault segments before the occurrence of the main rupture episodes. [ABSTRACT FROM AUTHOR]

Published
2004
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36. The Ms = 6.2, June 15, 1995 Aigion earthquake (Greece): evidence for low angle normal faulting in the Corinth rift.

Author

Bernard, P., Briole, P., Meyer, B., Lyon-Caen, H., Gomez, J.-M., Tiberi, C., Berge, C., Cattin, R., Hatzfeld, D., Lachet, C., Lebrun, B., Deschamps, A., Courboulex, F., Larroque, C., Rigo, A., Massonnet, D., Papadimitriou, P., Kassaras, J., Diagourtas, D., and Makropoulos, K.

Abstract

We present the results of a multidisciplinary study of the Ms = 6.2, 1995, June 15, Aigion earthquake (Gulf of Corinth, Greece). In order to constrain the rupture geometry, we used all available data from seismology (local, regional and teleseismic records of the mainshock and of aftershocks), geodesy (GPS and SAR interferometry), and tectonics. Part of these data were obtained during a postseismic field study consisting of the surveying of 24 GPS points, the temporary installation of 20 digital seismometers, and a detailed field investigation for surface fault break. The Aigion fault was the only fault onland which showed detectable breaks (< 4 cm). We relocated the mainshock hypocenter at 10 km in depth, 38 ° 21.7 ′ N, 22 ° 12.0 ′ E, about 15 km NNE to the damaged city of Aigion. The modeling of teleseismic P and SH waves provides a seismic moment Mo = 3.4 1018 N.m, a well constrained focal mechanism (strike 277 °, dip 33 °, rake − 77°), at a centroidal depth of 7.2 km, consistent with the NEIC and the revised Harvard determinations. It thus involved almost pure normal faulting in agreement with the tectonics of the Gulf. The horizontal GPS displacements corrected for the opening of the gulf (1.5 cm/year) show a well-resolved 7 cm northward motion above the hypocenter, which eliminates the possibility of a steep, south-dipping fault plane. Fitting the S-wave polarization at SERG, 10 km from the epicenter, with a 33° northward dipping plane implies a hypocentral depth greater than 10 km. The north dipping fault plane provides a poor fit to the GPS data at the southern points when a homogeneous elastic half-space is considered: the best fit geodetic model is obtained for a fault shallower by 2 km, assuming the same dip. We show with a two-dimensional model that this depth difference is probably due to the distorting effect of the shallow, low-rigidity sediments of the gulf and of its edges. The best-fit fault model, with dimensions 9 km E–W and 15 km along dip, and a 0.87 m uniform slip, fits InSAR data covering the time of the earthquake. The fault is located about 10 km east-northeast to the Aigion fault, whose surface breaks thus appears as secondary features. The rupture lasted 4 to 5 s, propagating southward and upward on a fault probably outcropping offshore, near the southern edge of the gulf. In the shallowest 4 km, the slip – if any – has not exceeded about 30 cm. This geometry implies a large directivity effect in Aigion, in agreement with the accelerogram aig which shows a short duration (2 s) and a large amplitude (0.5 g) of the direct S acceleration. This unusual low-angle normal faulting may have been favoured by a low-friction, high pore pressure fault zone, or by a rotation of the stress directions due to the possible dip towards the south of the brittle-ductile transition zone. This fault cannot be responsible for the long term topography of the rift, which is controlled by larger normal faults with larger dip angles, implying either a seldom, or a more recently started activity of such low angle faults in the central part of the rift. [ABSTRACT FROM AUTHOR]

Published
1997
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