| From 2008 to 2020,it was located in yutian area in the intersection area of the north Altyn Tagh fault,Longmuco fault and Guozhacuoo fault,in a part of the junction area of the eastern boundary of the West Kunlun block and the western boundary of Bayan Har block.The 2008 Mw7.1 earthquake,2012 Mw6.2 earthquake,2014 Mw6.9 earthquake and 2020 Mw6.3 earthquake occurred successively.In the region with a distance of100 km,several moderate and strong earthquakes have occurred continuously for a short period of time.Scientific questions such as seismogenesis mechanism and triggering relationship behind them are impressive,such as whether there is a stress triggering mechanism between the Yutian strong earthquake group at the end of the Altyn fault zone.Did it trigger the Yutian earthquakes of 2012,2014 and even 2020? For example,will the2020 Yutian earthquake be the last of the yutian earthquake cluster,and what is the trend of earthquake risk in the future? Trying to answer these questions can help us understand the evolution mechanism of seismogenic faults and local structures,and deepen the seismic risk of the cascade zone of the North Altyn,Kalakushi and Longmuco faults.In consideration of the advantages of synthetic aperture radar interferometry,such as high precision,wide coverage and all-weather,as well as the impact of the dry climate on the sparsely populated Yutian area,we decided to study these earthquakes based on In SAR technology.In this paper,the coseismic displacement field of the 2020 Yutian Mw6.3 earthquake was reconstructed using free Sentinel-1A IW lifting rail wide data from the European Space Agency,and the fault parameters and slip distribution results were inverse deduced.The reliable geometric parameters and kinematic slip distribution properties of the seismogenic fault were obtained.The results show that: The rupture length of the seismogenic fault is 12.5km,the width is 7.5km,and the moment magnitude of the inversion is Mw6.3.The coseismic slip is mainly distributed in the depth range of 6-9km underground,the slip momentum is about 0.94 m,and the average slip angle is-107.73°.The earthquake is mainly normal fault movement and has left-lateral strike-slip movement.It is preliminarily confirmed that the seismogenic structure of the earthquake is the fault in the middle of the small basin at the eastern foot of the Qiongmuzitag fault.We obtain the coseismic deformation fields of the 2008 and 2014 Yutian earthquakes using In SAR data and various methods,and analyze the two earthquakes in detail.Based on the parameters of the complex fault model in the existing research results,the fault slip models of the 2008 and 2014 Yutian earthquakes are inverted.To 2020 in field seismic research results,the sliding model to calculate the order issued in three earthquakes occurred on the fault of coseismic coulomb stress change,from the calculation results in field earthquake in 2008 is likely to trigger the in field earthquake in 2014,a single in field earthquake in 2014 to 2020 in field seismic slightly trigger,However,the cumulative stress changes of the 2008 and 2014 Yutian earthquakes inhibited the occurrence of the 2020 Yutian earthquake.Finally,we calculate and analyze the stress disturbance of large and medium fault within 200 km in Tian area,and the results show that: The occurrence of three Yutian earthquakes adjusted the stress distribution in this area,which increased the seismic risk of the southwest-northeast fault zone in Yutian area,and reduced the seismic risk of the northwest-southeast fault zone.Meanwhile,the seismic risk of Yutian area still cannot be ignored. |
