Did the 2008 Mw 7.9 Wenchuan Earthquake Trigger the Occurrence of the 2017 Mw 6.5 Jiuzhaigou Earthquake in Sichuan, China?

2018 ◽  
Vol 123 (4) ◽  
pp. 2965-2983 ◽  
Author(s):  
Ke Jia ◽  
Shiyong Zhou ◽  
Jiancang Zhuang ◽  
Changsheng Jiang ◽  
Yicun Guo ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Jiuzhaigou Earthquake ◽  
Earthquake Trigger

Evidence of Fault Immaturity from Shallow Slip Deficit and Lack of Postseismic Deformation of the 2017 Mw 6.5 Jiuzhaigou Earthquake

2020 ◽  
Vol 110 (1) ◽  
pp. 154-165 ◽  
Author(s):  
Yuexin Li ◽  
Roland Bürgmann ◽  
Bin Zhao
Keyword(s):  
Wenchuan Earthquake ◽  
Fault Zone ◽  
Surface Deformation ◽  
Strike Slip ◽  
Stress Change ◽  
Depth Interval ◽  
Postseismic Deformation ◽  
Jiuzhaigou Earthquake ◽  
2008 Wenchuan Earthquake ◽  
Slip Deficit

ABSTRACT The Mw 6.5 Jiuzhaigou earthquake occurred on 8 August 2017 36 km west-southwest of Yongle, Sichuan, China. We use both ascending and descending Interferometric Synthetic Aperture Radar (InSAR) data from Sentinel-1 and coseismic offsets of four Global Positioning System sites to obtain the coseismic surface deformation field and invert for the fault geometry and slip distribution. Most slip of the left-lateral strike-slip earthquake occurred in the 3–10 km depth interval with a maximum slip of about 1 m and a large shallow slip deficit (SSD). An eight-month InSAR time-series analysis documents a lack of resolvable postseismic deformation, and inversions for the distribution of postseismic slip demonstrate the lack of shallow afterslip. We argue that the observations of a pronounced SSD and no early afterslip of the Jiuzhaigou earthquake are indicative of an immature fault and that all incipient young strike-slip faults likely feature a SSD. We would expect a complex rupture geometry with distributed coseismic failure in the uppermost part of the brittle crust during the fault-zone development. As faults mature, they straighten out, develop a localized fault-zone core, and the SSD diminishes. By calculating the static Coulomb stress change and nine-year viscoelastic stress change caused by the Wenchuan earthquake, we also show that the 2008 Wenchuan earthquake did not significantly affect the time of occurrence of the 2017 Jiuzhaigou earthquake.

Geodetic inversion of complex fault geometries for strong earthquakes

2020 ◽  
Author(s):  
Yong Zhang ◽  
Yueyi Xu ◽  
Rongjiang Wang
Keyword(s):  
Wenchuan Earthquake ◽  
Moment Tensor ◽  
Seismic Inversion ◽  
Rupture Velocity ◽  
Fault Geometry ◽  
Gorkha Earthquake ◽  
Jiuzhaigou Earthquake ◽  
Geodetic Inversion ◽  
2015 Gorkha Earthquake ◽  
Fault Parameters

<p>The fault geometry closely controls earthquake rupture process. Previous seismic inversion of the fault geometry is to derive the multiple-point moment tensor solutions. Because of the trade-off between the moment tensor and rupture velocity, the inversion has high instabilities. In contrast, geodetic inversion has less unknowns, since there is no need to solve for rupture velocity. But from the elastic dislocation theory, the relations between the surface deformation and sub-fault parameters (i.e. strike, dip and rake) are nonlinear. In this study, we develop a linear technique to invert geodetic data for sub-fault moment tensors. From the sub-fault moment tensor solutions, the strike, dip, rake, and their spatial variations can be estimated, which provide valuable information for assessing the complexities in fault geometry. We applied this technique to several significant earthquakes, i.e., the 2008 Mw7.9 Wenchuan earthquake, the 2015 Mw7.8 Gorkha earthquake, and the 2017 Mw6.5 Jiuzhaigou earthquake. The results of the 2008 Wenchuan earthquake suggest that the strike, dip and rake are all variable from southwest to northeast, which are well consistent with the aftershock distributions and mechanisms. The dip variations of the 2015 Gorkha earthquake suggest the earthquake has ruptured a listric fault (dep decreases with depth). Particularly, a dip anomaly appears in the northeast corner of the rupture area, indicating a geometric barrier accounting for the slip gap between the mainshock and largest Mw7.3 aftershock. For the 2017 Jiuzhaigou earthquake, two right-stepping and left-lateral strike-slip segments were distinguished. Accordingly, a compressional step-over was identified between the two segments.</p>

scholarly journals Did the 2008 Wenchuan earthquake trigger a change in the conduct of research on seismic risk?

2020 ◽  
Vol 125 ◽  
pp. 104628 ◽  
Author(s):  
Qiang Zhang ◽  
Qibin Lu ◽  
Xuanting Ye ◽  
Shiling Xu ◽  
Leesa K. Lin ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Seismic Risk ◽  
2008 Wenchuan Earthquake ◽  
The 2008 Wenchuan Earthquake ◽  
Earthquake Trigger
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