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The 2018 M w 7.9 Offshore Kodiak, Alaska, Earthquake: An Unusual Outer Rise Strike‐Slip Earthquake
Author(s) -
Guo Rumeng,
Zheng Yong,
An Chao,
Xu Jianqiao,
Jiang Zhongshan,
Zhang Lupeng,
Riaz Muhammad Shahid,
Xie Jun,
Dai Kun,
Wen Yangmao
Publication year - 2020
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 - 10.1029/2019jb019267
Subject(s) - seismology , geology , aftershock , submarine pipeline , hypocenter , interplate earthquake , earthquake rupture , tectonics , intraplate earthquake , tsunami earthquake , slip (aerodynamics) , slow earthquake , strike slip tectonics , foreshock , stress field , induced seismicity , fault (geology) , geotechnical engineering , physics , thermodynamics , finite element method
The rupture process of the 2018 M w 7.9 offshore Kodiak (Alaska) earthquake is still in hot dispute because of a lack of offshore observations, thus causing difficulties for understanding seismogenic tectonics and tsunami hazards. In this study, teleseismic body waves, high‐rate GPS, seismic waves preceding tsunami waves, static GPS, and tsunami data are jointly used to resolve the faulting geometry and coseismic slip distribution of the offshore Kodiak earthquake. Tests of a series of finite fault rupture models illustrate that an optimal five‐fault model can reconcile all available data sets well. The results reveal that the asperity on each fault segment is located near the hypocenter, with peak slip of ~7.8 m. The aftershock loci appear to be complementary to the mainshock slips, demonstrating the velocity‐strengthening regions that predominantly slip aseismically. Based on a tectonic stress field analysis, we propose that the 2018 Kodiak earthquake is attributed to a combination of enhanced tensional stress following the 1964 M w 9.2 Alaska earthquake and compressional stress produced by the collision of the Yakutat terrane with North America.