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Multifault Models of the 2019 Ridgecrest Sequence Highlight Complementary Slip and Fault Junction Instability
Author(s) -
Jia Zhe,
Wang Xin,
Zhan Zhongwen
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 - 10.1029/2020gl089802
Subject(s) - foreshock , seismology , geology , aftershock , slip (aerodynamics) , geodetic datum , hypocenter , fault (geology) , instability , geodesy , induced seismicity , mechanics , engineering , physics , aerospace engineering
The 2019 Ridgecrest M w 6.4 and M w 7.1 earthquakes ruptured a complex fault system, posing challenges in understanding their physical processes. Modeling of the ruptures relies on fault geometries at depth, which are usually assumed based on surface traces and aftershocks. Here we use seismic and geodetic data to jointly constrain the fault geometries and slip distributions. We first represent the first‐order rupture processes with a series of subevents, then conduct slip inversions with subevent‐guided fault geometries. We find that the foreshock sequentially ruptured the NW and SW striking faults starting from their junction. The mainshock initiated at a complex three‐fault junction along the extension of the foreshock NW rupture, with major slip first occurring bilaterally near the hypocenter and then minor unilateral slip later to the southeast end. The slip distributions of the foreshock and mainshock are complementary to each other on the overlapping fault section.