Inversion Of Co-seismic Slip Distribution Of Jiuzhaigou Earthquake Based On Sentinel-1A Satellite Data

Among the existing natural geological disasters,the destructive power of the earthquake is the strongest.Most of its occurrence is caused by the sudden release of energy inside the crust after long-term accumulation.According to the difference of the magnitude,the degree of damage caused by the earthquake It is also different.An earthquake with a relatively large magnitude,especially where it occurs close to a residential area,will cause particularly large losses.Therefore,it is very important to strengthen the research on earthquakes.The rise of InSAR technology has brought a lot of room for development in seismic research.In recent years,researchers have continuously developed and innovated InSAR technology,which has made its ability to monitor co-seismic deformation of earthquakes greatly improved.To improve,it is favored by researchers with its own advantages such as high precision,low cost and all-weather.The Mw6.6 earthquake occurred on August 8,2017 in Jiuzhaigou,a famous scenic spot in Sichuan Province.The epicenter was 33.20°N,103.82°E.This earthquake lead 25 people died.About 5 hundreds of people were injured,lots of houses were damaged,and local tourist sites in Jiuzhaigou were irreparably damaged.Because the earthquake occurred in a remote and complex area,and the relevant ground deformation observation data is not sufficient,so in view of the advantages of InSAR technology,this method is given priority.In this paper,the differential interference data of the ascending and descending Sentinel-1A satellites is used as the basis of this study.The coseismic deformation observation data of the Jiuzhaigou earthquake in Sichuan and the distribution of fault slips are inverted.The main research conclusions are summarized.as follows:(1)Sentinel-1A satellite data covering the entire earthquake occurrence area was collected,and the LOS co-seismic deformation field of the ascending and descending orbit of the 2017 Jiuzhaigou earthquake in Sichuan was acquired using D-InSAR technology.Taking the near NS direction as the boundary of the coseismic deformation field of this earthquake,the coseismic deformation field is divided into two parts:northwest and southeast,and it is defined as a negative value when the line of sight deformation of the target is far away from the satellite.It is positive when the line of sight is deformed.The maximum uplift values of line-of-sight deformation are about 0.147m(T62),0.146m(T55),0.137m(T128),and the maximum settlement values are about 0.121m(T62),0.196m(T55),0.195m(T128).(2)For the same area,the two ascending orbital deformation fields show that the northwestern plate is uplifting area and the southeastern plate is subsidence area,and the deformation trend observed using the orbital data images is diametrically opposite to the ascending orbital deformation field.The observation of the opposite deformation characteristics of the lifting and lowering rails indicates that the rupture nature of the earthquake is dominated by strike-slip movement,that is to say,the resulting surface deformation is dominated by the horizontal direction.The trend of the fault is 150°,and the dip angle of the fault is 78°.(3)The slip distribution of the fault is mostly distributed at a depth of 3?14Km.The maximum slip of the fault is about 9km deep below the surface,reaching 0.4m.The total seismic moment of the earthquake is M₀=9.35×10¹⁸N·m,which is about Mw6.6.Compare the results of this earthquake with the results of seismic research published by authoritative agencies such as China Earthquake Network Center(CENC),the United States Geological Survey(USGS),and the results are basically the same,confirming the reliability of the data processing results.