A new seismotectonic model for the Lesser Antilles

The seismic hazard levels currently used as a reference for the French Lesser Antilles are derived from studies carried out in 2002. Scientific knowledge has increased considerably over the last 20 years, justifying an update. The identification of the elements required to produce a new seismic hazard calculation follows a request from the French Ministry of Ecological Transition’s Direction Générale de la Prévention des Risques (MTECT) to Epos-France’s Action Transverse Sismicité (ATS). One of the three priorities identified was the establishment of a new seismotectonic zoning system incorporating the most up-to-date geological and geophysical data. To this end, a study was carried out by Océane Foix at the Geosciences Montpellier laboratory of the University of Montpellier, in collaboration with the Institut de Radioprotection et de Sûreté Nucléaire, and financed by the MTECT.

The proposed model can now be used to calculate the seismic hazard. It can be updated in the light of new knowledge, which could help reduce certain uncertainties resulting from a lack of information on the active tectonics and seismicity of certain zones of the Lesser Antilles arc. Thanks to a better depth resolution of the plunging plate roof and upper plate Moho geometries, this study has enabled a complete revision of the crustal model, and a redefinition of the subduction interface and the subducted plate. The authors propose to define a model for mantle seismicity and volcanic seismicity, not currently taken into account.

To know more :

Le rapport ministériel et les données sont disponibles sur le site de l’OREME : Foix, Océane; Mazzotti, Stéphane; Jomard, Hervé (2023). A New Seismic Source Zone Model for Lesser Antilles Seismic Hazard Assessment – Data. OSU OREME. (Dataset). DOI: 10.15148/dd520135-7656-4e80-91fe-f0284accbc76