Séminaire ISTerre

Mapping Mantle Wedge Seismicity for Ground Motion Assessment: The Lesser Antilles Subduction Zone Case (Guadeloupe, Martinique)

vendredi 9 octobre 2026 - 14h00
Océane Foix - ISTerre
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Estimating seismic hazard in a given area requires defining the ground response to seismic waves during an earthquake. This ground response depends on the source, the path, and site effects. Regarding source-to-site characteristic variations, each seismogenic source is defined by specific ground motion laws. At subduction zones, seismogenic sources come in a wide range, from crustal to interface and intraslab sources. Thanks to advances in seismic instrumentation, more and more seismicity has been observed and recorded in the forearc mantle wedge (MW), as in New Zealand, Peru, the Lesser Antilles, Greece, and the Alps. Nowadays, this seismicity is not properly accounted for in the seismic hazard calculation chain, and it is not considered as a specific seismic source. Its seismicity is instead distributed among other sources, such as the crust of the upper or lower plate, or along the megathrust of the plate interface. This means that the distances between the MW hypocenters and the hazard calculation sites are not properly resolved. The Lesser Antilles subduction zone, home to French territories, has the highest seismic hazard level in France. In previous seismic hazard estimations, MW seismicity was not considered. To assess its significance for the islands of Guadeloupe and Martinique, we mapped the MW seismicity to build and refine a specific seismic catalog, and evaluated, from onshore accelerometric stations, the peak ground acceleration and velocity. In this presentation, I invite you to explore and discuss our results and their implications for seismic hazard at subduction zones worldwide.

Equipe organisatrice : Géophysique des risques sismiques et gravitaires

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

The emergence of proto-plate boundaries from lithospheric drips with grain-damage

mercredi 7 octobre 2026 - 11h00

Pr David Bercovici - Yale University

Equipe organisatrice : Géodynamo

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Round-table on natural carbon capture and other climate-related topics

mercredi 7 octobre 2026 - 14h00

Pr David Bercovici - Yale University, Yale Center for Natural Carbon Capture

Equipe organisatrice : Organisation labo

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Study of the mantle transition zone by combining earthquake data and seismic noise data: application to the Alps and Massif Central

vendredi 9 octobre 2026 - 10h00

Piel Pawlowski - ISTerre

Equipe organisatrice : Ondes et structures

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Mapping Mantle Wedge Seismicity for Ground Motion Assessment: The Lesser Antilles Subduction Zone Case (Guadeloupe, Martinique)

vendredi 9 octobre 2026 - 14h00

Océane Foix - ISTerre

Equipe organisatrice : Géophysique des risques sismiques et gravitaires

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Statistical physics of creep rupture of heterogeneous materials

jeudi 15 octobre 2026 - 11h00

JUAN CARLOS VERANO ESPITIA  - ISTerre - Aalto University (Finlande)

Equipe organisatrice : Mécanique des failles

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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The Seismic Response of Faults to Weak Perturbations: A New Probe Into Earthquake Physics and Fault State

vendredi 6 novembre 2026 - 11h00

Eric Beaucé - ISTerre

Equipe organisatrice : Cycle sismique et déformations transitoires

Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères

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TBA

vendredi 20 novembre 2026 - 11h00

Farzaneh Mohammadi - ENS Paris

Equipe organisatrice : Cycle sismique et déformations transitoires

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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