Transverse thematic action Seismicity

Outline

Most of the work on characterizing and monitoring French seismicity and the associated seismic hazard is carried out by teams from organizations that are members of the Epos-France consortium, and this work is largely based on data from Epos-France’s observation resources.

In 2016, several partners in the Résif-Epos Research Infrastructure wished to formalize this state of affairs within the framework of the RI, and the Seismicity Transverse Action (ATS) was born. The aim of the ATS was to coordinate all work on seismicity within a single structure, in order to increase the efficiency and visibility of the work carried out. In particular, the aim was to produce and distribute products based on Résif data, focusing on knowledge of French seismicity and the associated hazard.

Today, the ATTS (Action transverse thématique Sismicité) is part of the Groupe thématique Sismologie of Epos-France. It has become a major player in seismic hazard characterization projects in France, both in the West Indies and in France itself, and has also made a major contribution to the emergence of a structured action to develop the study of active faults in France (Fact).

Contact: Frédéric Masson, Eost

Objectives

The ATTS is subdivided into six axes, each with its own objectives.

Axis 1 and 2: multi-origin bulletin and reference catalog

The bulletin contains, for each seismic event, all the information (hypocenters, phase arrival times, magnitude, etc.) resulting from the analysis of data acquired by the seismological networks of Epos-France and other French or foreign networks.

For each event in the multi-origin bulletin, the catalog contains the solution deemed most relevant. It is the reference catalog for French seismicity. It is intended for all those concerned by seismicity.

• Bulletin contacts: Marc Grunberg (Eost) and Gilles Mazet-Roux (CEA)
• Catalog contacts: Sophie Lambotte (Eost) and Bruno Hernandez (CEA)

Area 3: Macroseismic data, historical and contemporary seismicity

ATTS axis 3 on the collection and analysis of macroseismic data from historical and contemporary seismicity includes all activities relating to the acquisition and management of macroseismic data and the assessment of intensities. It also oversees the inter-agency Macroseismic Intervention Group (GIM), whose mission is to establish macroseismic intensities (severity of ground shaking) within a short time of an earthquake in France that has caused significant damage to buildings.

• Contacts: Christophe Sira (Eost) and Ludmila Provost (IRSN)

Axis 4: Shakemap

The aim of Axis 4 “ShakeMap” is to generate a nationwide map of earthquakes, both inside and outside mainland France.  This shakemap is a result that can be rapidly made available to all types of users (scientists, general public, authorities), but also a research and application tool in the field of seismic risk.

• Contacts Antoine Schlupp (Eost) and Didier Bertil (BRGM)

Axis 5: Active faults France (Fact)

From a seismotectonic point of view, metropolitan France, like its neighboring countries in Western Europe, can today be defined as an intraplate zone with a strong structural heritage and a low deformation rate. The aim of the “Active faults France” axis is to gain a better understanding of the seismicity associated with active faults in France and the processes behind this seismicity, by building up the most comprehensive database possible of active faults in the Quaternary.

• Contacts: Jean-François Ritz (Géosciences Montpellier) and Stéphane Baize (IRSN) – Alternate L. Audin (ISTerre)
• List of 2024 referents of the Active Faults Axis France (pdf)

Axis 6: Hazard

Axis 6 “Aléa” aims to encourage interaction between all players (university and CNRS laboratories, organizations such as BRGM, IRSN or CEA, public and private companies) contributing to the definition of seismic hazard in order to :

• compile the databases needed to assess the seismogenic potential of seismic sources in France,
• promote the development of new seismotectonic and seismic hazard models incorporating the latest research findings.

The work of Axis 6 has led to the Alceste (Aléa sismique de l’Hexagone) program, supported by the French Ministry for Ecological Transition and Territorial C

• Contacts: Stéphane Mazzotti (Géosciences Montpellier) et Hervé Jomard (IRSN)