Inversion Of Longmenshan Fault Activity Parameters Using GPS And InSAR Observations

Longmen Shan fault is located in the eastern margin of the Q inghai-Tibet Plateau,which is one of the most active areas of crustal movement in mainland C hina.The study of the active mechanism of the Longmenshan fault not only provides a scientific basis for our study of Q inghai-Tibet Plateau crustal movement,but also provides valuable information for the prediction of earthquakes.Based on the GPS observation data,the crustal movement characteristics of the Longmenshan fault area are analyzed,and the parameters of slip and rotation of the Longmenshan fault are studied in combination with the dislocation-disclination model.Secondly,based on the dislocation model,the GPS and InSAR deformation data are used to study the the activities of PingWu-Q ingchuan Fault.The conclusions are as follows:(1)The velocity field in the Longmen mountains is fitted by IDW based on the data of CMONOC 09-11 reference station.The velocity field shows that there is a velocity gradient on the East and west sides of the Longmen mountain fault,which is 8mm/a.The least square method is used to calculate the strain field in Longmen mountainous area.The strain distribution shows that the Longmen mountain fault is tensile strain released in post-seismic.(2)The main activities of the characteristics of Longmenshan fault is right lateral slipping with thrusting at this stage.The maximum slip rate is 3.6mm/a,and the maximum thrust rate is 2.8mm/a.Longmen mountain fault exists fault rotation,but the value of rotation is very small.The movement of the crust in the Longmenshan area which shows a clockwise rotation trend may be related to the rotational movement of the Longmenshan fault.(3)The inversion result shows that the GPS inversion results mainly reflect t he characteristics of striking,and InSAR inversion results mainly reflect the characteristics of dipping by GPS?InSAR deformation data inversion separately.So it is impossible to study the fault activity entirely because of limitation of single type data.The activity of the characteristics of Pingwu-Qingchuan fault is mainly right lateral slipping and thrusting according to the joint inversion of GPS and InSAR deformation data.The strike slip rate is 1 ~ 1.2mm/a,and the thrust rate is 0.5mm/a.(4)The critical problem of joint inversion is to determine the relative weight,which can directly affect the joint inversion results.Compared with the conventional joint inversion,the relative weight of the constraint inversion can improve the accuracy and validity of the inversion result.