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Fault Geometry and Slip Distribution of the 2013 Mw 6.6 Lushan Earthquake in China Constrained by GPS, InSAR, Leveling, and Strong Motion Data
Author(s) -
Huang Yong,
Qiao Xuejun,
Freymueller Jeffrey T.,
Wang Qi,
Yang Shaomin,
Tan Kai,
Zhao Bin
Publication year - 2019
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2019jb017451
Subject(s) - geology , seismology , aftershock , interferometric synthetic aperture radar , slip (aerodynamics) , earthquake rupture , seismic gap , thrust fault , fault (geology) , geodesy , global positioning system , asperity (geotechnical engineering) , tectonics , synthetic aperture radar , remote sensing , geotechnical engineering , telecommunications , physics , computer science , thermodynamics
Abstract On 20 April 2013, an Mw 6.6 Lushan earthquake occurred on the southwestern segment of the Longmen Shan fault belt, which is the tectonic block boundary between the eastern Tibetan plateau and the Sichuan basin. Seismic reflection profiles and aftershock relocation indicate that there exists a back thrust fault in the source region but whether it is ruptured during the Lushan earthquake remains controversial. Here the precise leveling data are firstly used together with Global Positioning System (GPS), Interferometric Synthetic Aperture Radar (InSAR), and strong motion data to invert for the fault geometry and slip distribution associated with the earthquake. The joint inversion result shows that the Lushan earthquake occurred on a blind thrust fault with strike N208.5 °E and dip 42.1° to the NW and did not rupture the back reverse fault. The coseismic slip model reveals the Lushan earthquake involves the rupture of one major asperity. The coseismic slip is mainly concentrated on a steeply dipping fault plane. The coseismic rupture terminates on the southwestern side of the seismic gap between the Wenchuan and Lushan earthquakes. Topographic stress may be the dominant mechanism of coseismic rupture termination.