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Seismic Stereometry Reveals Preparatory Behavior and Source Kinematics of Intermediate‐Size Earthquakes
Author(s) -
Mordret A.,
Brenguier F.,
Causse M.,
Boué P.,
Voisin C.,
Dumont I.,
Ver F. L.,
Ampuero J. P.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl088563
Subject(s) - seismology , geology , earthquake rupture , remotely triggered earthquakes , interferometric synthetic aperture radar , tectonics , kinematics , earthquake simulation , san andreas fault , fault (geology) , foreshock , nucleation , earthquake prediction , interplate earthquake , seismic gap , geodesy , subduction , remote sensing , synthetic aperture radar , aftershock , physics , classical mechanics , thermodynamics
Although moderate‐size earthquakes are poorly studied by lack of near‐fault observations, they can provide key information about larger damaging earthquakes. Here we propose a new approach, inspired by double‐difference relocation, that uses high‐coherency waveforms recorded at neighboring sensors, to study the preparation phase and dynamics of moderate‐size earthquakes. We validate this technique by analyzing the 2016, M w 5.2 Borrego Springs earthquake in Southern California and find consistent rupture velocities of 2 km/s highlighting two main rupture asperities. The analysis of the 2019, M l5.2 Le Teil earthquake in France reveals slow nucleation at depth that migrates to the surface and propagates northward with a velocity of ∼ 2.8 km/s, highlighting two main rupture events also imaged by InSAR. By providing unprecedented resolution in our observation of the rupture dynamics, this approach will be useful in better understanding the preparation phase and rupture of both tectonic and induced earthquakes.