A hybrid source mechanism of the 2017 Mw 6.5 Jiuzhaigou earthquake revealed by the joint inversion of strong-motion, teleseismic and InSAR data

Zheng，Ao1,2; Yu，Xiangwei3; Xu，Wenbin4,5; Chen，Xiaofei2; Zhang，Wenbo3

2020-08-20

10.1016/j.tecto.2020.228538

TECTONOPHYSICS   影响因子和分区

0040-1951

1879-3266

As occurred during the tourist season, the 2017 M 6.5 Jiuzhaigou (China) earthquake led to destructive damages. The seismogenic fault of this event was merely speculated to be the northern extension of the Huya fault, while no apparent surface ruptures were discovered in the field investigation. Previous studies and released moment tensor solutions indicated the Jiuzhaigou earthquake was dominated by left-lateral strike slip with partial normal-slip component. It seems unintelligible that the normal slip occurred in this event as the epicenter was located near the boundary of convergent blocks. Hence, a reasonable and elaborate source rupture model is necessary to investigate such a blind fault and the role it plays in the complex fault system of this region. Combining space-based geodetic, teleseismic or regional seismic observations can provide detailed information about earthquake ruptures. We first attempted to determine the fault geometry using the Bayesian approach with synthetic aperture radar interferograms (InSAR). And then the fault geometry was refined based on the relocated aftershock distribution, and a two-segment fault model was constructed. Based on the two-segment model, we resolved the source rupture process of the 2017 Jiuzhaigou earthquake through the joint inversion of strong-motion, teleseismic body-wave and InSAR data. The inversion results reveal a hybrid source mechanism, in which normal and thrust slips coexist besides the strike-slip component. We suggest that the eastward motion with the extrusion of the lower crustal flow in the northeastern margin of the Bayan Har block is responsible for such a faulting behavior. The co-seismic Coulomb stress changes show a significant stress loading in the western segment of the Tazang fault, increasing its seismic hazard. Due to the lack of aftershocks to the southeast of the seismogenic fault, the probably enhanced seismicity in the northern segment of the Huya fault is also worth further attention.

Finite fault model InSAR Jiuzhaigou earthquake Joint inversion Tectonic implications

SCI ; EI

英语

其他

National Natural Science Foundation of China[41674056][41804015][41374105][U1901602][41790465] ; National Key Research and Development Program of China[2019YFC1509205]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:000558906700016

ELSEVIER

20202608865229

Earthquakes ; Strike-slip faults ; Bayesian networks ; Fault slips

Seismology:484 ; Earthquake Measurements and Analysis:484.1 ; Radar Systems and Equipment:716.2 ; Combinatorial Mathematics, Includes Graph Theory, Set Theory:921.4

GEOSCIENCES

2-s2.0-85086713136

Scopus

1.School of Earth and Space Sciences,University of Science and Technology of China,Hefei,China
2.Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,China
3.College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing,China
4.School of Geosciences and Info-Physics,Central South University,Changsha,China
5.Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring (Central South University),Ministry of Education,Changsha,China

Zheng，Ao,Yu，Xiangwei,Xu，Wenbin,et al. A hybrid source mechanism of the 2017 Mw 6.5 Jiuzhaigou earthquake revealed by the joint inversion of strong-motion, teleseismic and InSAR data[J]. TECTONOPHYSICS,2020,789.

Zheng，Ao,Yu，Xiangwei,Xu，Wenbin,Chen，Xiaofei,&Zhang，Wenbo.(2020).A hybrid source mechanism of the 2017 Mw 6.5 Jiuzhaigou earthquake revealed by the joint inversion of strong-motion, teleseismic and InSAR data.TECTONOPHYSICS,789.

Zheng，Ao,et al."A hybrid source mechanism of the 2017 Mw 6.5 Jiuzhaigou earthquake revealed by the joint inversion of strong-motion, teleseismic and InSAR data".TECTONOPHYSICS 789(2020).