EGU21-7913, updated on 04 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

A comprehensive quantification of error location uncertainties for the French earthquake catalog

Andres Felipe Peña Castro1,2, Sophie Lambotte1,2, Marc Grunberg2, Pierre Arroucau3, Jessi Mayor3,4, Guillaume Daniel3, and Jean Letort5
Andres Felipe Peña Castro et al.
  • 1Institut Terre et Environnement de Strasbourg, University of Strasbourg, Strasbourg, France (
  • 2École et Observatoire des Sciences de la Terre, University of Strasbourg, Strasbourg, France (
  • 3EDF/DI/TEGG, Seismic Hazard Group, 905 Avenue du Camp de Menthe, 13097, Aix-en-Provence, France.
  • 4EDF R&D, 7 Boulevard Gaspard Monge, 91120, Palaiseau, France
  • 5Observatoire Midi Pyrénées, IRAP, CNRS UMR 5277, Université Paul Sabatier, Toulouse, France

Locating earthquakes has been a longterm problem in seismology that depends on multiple parameters like station density and spacing, azimuthal gap, velocity models, and phase pick precision. Here, we analyze the current state of the earthquake French catalog for the time period between 2010 until 2018, which we divide into different regions: the Alps, Massif Central, the West, the Pyrenees, the Grand-East and the North. We perform multiple location synthetic tests using as benchmark the earthquake catalog and the evolution of the French seismic network to quantify the improvements in 1) earthquake location through time and 2) the error locations and their uncertainties. For such endeavors, we use NonLinLoc to perform the synthetic tests varying, as input, the stations, the number of stations and phase picks, 1D velocity models and 3D velocity models, and to understand the changes in 1) earthquake hypocenters, 2) ellipsoidal errors and 3) posterior density functions. Then, we relocate the entire catalog using NonLinLoc including 3D velocity models (where available) and compare the hypocentral location differences when we relocate the catalog with 1D velocity models. Additionally, we estimate a quality factor for each of the located earthquakes and report the changes on the quality factor with the temporal evolution of the national seismic network. The resulting catalog and its associated error location will help future seismic hazard estimations in the Metropolitan French area.

How to cite: Peña Castro, A. F., Lambotte, S., Grunberg, M., Arroucau, P., Mayor, J., Daniel, G., and Letort, J.: A comprehensive quantification of error location uncertainties for the French earthquake catalog, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7913,, 2021.

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