Application Of InSAR And GPS Techniques In Interseismic And Coseismic Deformation

As a new kind of space geodesy techniques,In SAR(Interferometric Synthetic Aperture Radar)has been developed rapidly in last years.Due to its advantages of high precision,large coverage and day-and-night monitoring,In SAR has been widely applied to Topographic surveying and mapping,Volcano ground deformation,Earthquake-Crustal deformation cycle,etc.This paper analyzes the application of In SAR and GPS technologies in fields of interseismic deformation and coseismic deformation with western Jiali fault and 2015 Pishan earthquake.The main research contents and conclusions of this paper includes:1.Based on ISCE and Sta MPS data process software,we obtained the LOS(Light of Sight)ground deformation of western Jiali fault from 63 SAR images which were produced by Sentinel-1A,and we made some profiles crossing fault to analyze fault activities.The LOS deformation field indicates that Jiali fault and Bengcuo fault are right-lateral slip.We calculated relative speed according to crossing fault profiles,the results indicate that the relative speed of Bengcuo fault is 1.3 mm/a and the western Jiali fault is 1.9 mm/a.2.We collected and obtained the velocities of 36 GPS observation points in the ITRF reference frame,we also made a GPS velocity profile to analyze across two blocks.The result indicates faults in the area are right-lateral slip;the velocity that is perpendicular to the fault presents a linear decreasing trend which suggests that the movement pattern of this area is redistributed,and this phenomenon also confirms the fact that the Tibet Plateau is gradually compressed due to the Indian plate pushing,caused that the Tibetan Plateau material escapes to the southeast.3.According to a screw dislocation model,the inversion results from In SAR observation data indicate that slipping rates of Bengcuo fault are 1.3 mm/a?2.9 mm/a with the locking depths of 8.3 km?11.1 km;the slipping rates of western Jiali fault are 1.7 mm/a?2.7 mm/a and the locking depths are 2.2 km?3.0 km;While in the east of western Jiali fault both slipping rates and locking depths are closed to 0.The inversion results from GPS data indicate locking depths of the fault are 19.6±10.8 km with slipping rates of 3.2±2.0 mm/a.Slipping rates of Bengcuo that are calculated from GPS data or In SAR data are almost equal,while locking depths are different,the main reason is the wide distribution of GPS stations.4.We calculated the strain field using GPS velocity field data based on multi-scale spherical wavelet.The result indicates there are a high-value of shear strain rates along Bengcuo fault and western Jiali fault showing strain accumulation in this area;surfacestrain rate along fault is almost unchanged showing there is no obvious expansion or compression across the fault;rotational-strain rate distribution is clockwise in western Jiali fault which indicates Jiali fault is right-lateral slip.Combined earthquake distribution and shear strain distribution,there are more earthquakes in the area with high shear strain rate.5.Based on Sentinel-1A In SAR data and GPS coseismic observation data,and using MPSO?MC?SDM,we inverted the geometric model of the seismogenic fault and the fault slip distribution of the 2015 Pishan earthquake.the results show that he seismogenic fault of Pishan earthquake should be a hidden fault with the length is 48 km,the width is 35 km,the strike angle is 111°,the dip angle is 19°,the average rake angel is 91°,and the buried depth is about 7.4 km.The maximum slip of the fault is 0.47 cm located at the depth of 10.6 km.