Confirmation and Characterization of the Rupture Model of the 2017 Ms 7.0 Jiuzhaigou, China, Earthquake
Authors:Zhang, Xu Xu, Li-Sheng Yi, Lei Feng, Wanpeng
Volume:92
Published:2021
Document Type:Article
Abstract:On 8 August 2017, an Ms 7.0 earthquake struck the Jiuzhaigou town, Sichuan Province, China, rupturing an unmapped fault, which is adjacent to the Maqu seismic gap in the Min Shan uplift zone in the easternmost part of the Bayan Har block. Having summarized the previous studies on the source of this earthquake, we confirmed the rupture model by jointly inverting the teleseismic P-wave and SH-wave data, Interferometric Synthetic Aperture Radar line-of-sight displacement data, and the near-field seismic and strong-motion data, a most complete dataset until now. The confirmation showed that a scalar seismic moment of 6:6 x 1018 N center dot m was released (corresponding to a moment magnitude of Mw 6.5), and 95% of the release occurred in the first 10 s. The slip area was composed of two asperities, with a horizontal extension of - 20 km and a depth range of - 2-15 km. A bilateral extending occurred at shallow depths, but the rupturing upward from deep depth dominated in the early time. The rupture process was found generally featuring the slip-pulse mode, which was related to the weak prestress condition. The aftershocks almost took place in gaps of the mainshock slip because of the coulomb stress change. Combining the aftershock relocations, aftershock focal mechanism solutions, and our confirmed rupture model, we suggest that the seismogenic fault was a northward extension of the mapped Huya fault. The occurrence of this earthquake made the Maqu seismic gap at a higher level of seismic risk, in addition to the moderate to high strain accumulation on the easternmost tip of the Kunlun fault system and the weak lower crust below.
Author Information
Corresponding Author:Xu, LS (通讯作者)，China Earthquake Adm, Inst Geophys, Beijing, Peoples R China.;Xu, LS (通讯作者)，China Earthquake Adm, Key Lab Earthquake Source Phys, Beijing, Peoples R China.
Reprint Address:Xu, LS (通讯作者)，China Earthquake Adm, Inst Geophys, Beijing, Peoples R China.;Xu, LS (通讯作者)，China Earthquake Adm, Key Lab Earthquake Source Phys, Beijing, Peoples R China.
Addresses:[Zhang, Xu; Xu, Li-Sheng] China Earthquake Adm, Inst Geophys, Beijing, Peoples R China; [Zhang, Xu; Xu, Li-Sheng] China Earthquake Adm, Key Lab Earthquake Source Phys, Beijing, Peoples R China; [Yi, Lei] Chinese Acad Sci, Qinghai Inst Salt Lakes, Key Lab Comprehens & Highly Efficient Utilizat Sa, Xining, Peoples R China; [Yi, Lei] Chinese Acad Sci, Qinghai Inst Salt Lakes, Qinghai Prov Key Lab Geol & Environm Salt Lakes, Xining, Peoples R China; [Feng, Wanpeng] Sun Yat Sen Univ, Sch Earth Sci & Engn, Guangdong Prov Key Lab Geodynam & Geohazards, Zhuhai, Peoples R China; [Feng, Wanpeng] Southern Marine Sci & Engn Guangdong Lab Zhuhai, Zhuhai, Peoples R China
E-mail Addresses:xuls@cea-igp.ac