SISMalp 1987-2023, the database listing earthquakes occurring between 1987 and 2023 in the western (French) Alps north of 43.5°N, has just been made available to the scientific community on Easy Data, the national reference warehouse for Earth system and environmental data.

The western Alpine arc is characterized by moderate but constant seismic activity. Numerous studies (geodynamic and seismological) have highlighted persistent scientific questions relating to :
– alpine dynamic processes and associated deformation rates (resulting from late continental collision phases)
– seismic hazard and risk assessment.

Seismic monitoring in the northern French Alps was launched in 1987 with the installation of the first Sismalp seismological network, hosted by the Observatoire des Sciences de la Terre of Grenoble Alpes University and managed by the Institut des Sciences de la Terre. Since 1987, the network has been updated over the years, keeping pace with technical developments in instrumentation, monitoring and data management. The homogenization of information over the period 1987-2023 was motivated by the need for a single instrumental seismic catalog. The final SISMalp-1987-2023 catalog contains 50,822 earthquakes with a completeness magnitude of less than 1, and can be used as a basis for all general seismotectonic and seismic risk assessment studies.

Sismicité des Alpes occidentales françaises entre 1987 et 2023 © M. Langlais @SISMalp

Seismicity of the French Western Alps between 1987 and 2023 © M. Langlais @SISMalp – To know more about this map

More information

  • Go to catalog (Entrepôt Easy Data)
  • Catalog authors: Mickael Langlais, Gael Janex, Philippe Guéguen, Agnès Helmstetter, Anne Paul, Jean Virieux, Emeline Maufroy, Jean-Noël Bouvier, ISTerre, Université Grenoble Alpes, USMB/CNRS/IRD/UGE, Grenoble, France
  • The database and the strategy followed to harmonize information over the period 1987-2023 are described in: Langlais M., Janex G., Guéguen P., Helmstetter A., Paul A. Virieux J., Maufroy E., Bouvier J.-N. 2024. SISMalp-1987-2023: The catalog of 1987-2023 earthquakes in the western (French) Alps north of 43.5°N. Scientific Data, under review. doi: 10.57932/bba3b3a3-e92e-4d90-92db-9b045684ed5d
  • Technical validation is described via an in-depth study of the influence of parameters and choices for local seismic tomography (LET), which inverts local-regional earthquake arrival time selections for P- and S-wave velocities in conjunction with hypocenter parameters. Reference: Virieux J., Paul A., Langlais M., Janex G., Guéguen P., Helmstetter A., Stehly L. 2024. Assessing the reliability of local earthquake tomography for crustal imaging: 30 years of records in the Western Alps as a case study, Geophysical Journal International, 236(1):99-118. doi :10.1093/gji/ggad378