Coseismic Deformation Characteristics of the 2017 Jiuzhaigou MS7.0 Earthquake Constrained by InSAR and GPS Observations
The focal mechanism of the 2017 Jiuzhaigou MS7.0 earthquake,inverted through seismic wave and InSAR observations,was mainly strike-slip,but the coseismic displace-ment observed by near-field GPS showed significant dip-slip characteristics in the northern section of the seismic fault.In view of this,we combines GPS and InSAR observation data to obtain rich coseismic deformation.Based on the Bayesian inversion of the geometric model of the fault,it compares and analyzes the differences in the coseismic slip distribu-tion inverted from three data sources:GPS only,InSAR only,and fused GPS/InSAR.Thereby,it gives the optimal slip distribution model of this earthquake.The results show that the optimal model has a strike of 150° for the seismic fault,an inclination of 56°,a maximum slip of about 1.3 m,located at a depth of 5.3 km underground,and a moment magnitude of MW6.5.Especially after adding the coseismic displacement of near-field GPS,the results show that in addition to the left-lateral strike-slip,there is also a dip-slip com-ponent in the northern section of the seismic fault.Based on the spatial distribution of the main active faults in the epicenter area,such as the Huya Fault and the Tazang Fault,this article speculates that the dip-slip property in the northern section of the seismic fault may be caused by maintaining the motion balance in the intersection area of the Tazang Fault and the Huya Fault.
The 2017 Jiuzhaigou MS7.0 earthquakeInSARGPSCoseismic slip distri-bution
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