Research On InSAR Seismic Source Parameter Inversion And The Triggering Relationship Between Earthquakes

InSAR technology has been successfully applied to the source parameters inversion of a lot of independent earthquakes or earthquake sequences.Using InSAR technology to do seismic research,owing to the high precision,large coverage and high continuity,we can not only get the scope and extent of earthquake damage more directly but also make the inversion results of source parameters more accurate.The study of triggering relationship between earthquakes is an important way to explore the mechanism of earthquake generation and triggering.The change stress of faults after earthquake is an important reference for analyzing the triggering relationship between earthquakes and the risk of earthquakes.Based on the coseismic deformation fields obtained by InSAR technology,the inversion of source parameters and the static Coulomb stress transformation model,in this paper,the following research works have been done for several earthquakes in southwest Taiwan and central Italy in recent years:(1)D-InSAR,the basic theory of earthquake and the method of seismic source inversion are introduced,in this paper,and the nonlinear inversion and linear inversion methods of focal parameters are systematically summarized.(2)The coseismic deformation fields of 2010 Mw 6.3 Jiashian and 2016 Mw 6.4Meinong earthquakes in Taiwan are obtained by InSAR data.The deformations of the two earthquakes are mainly uplifting and the results coincide with the GPS observations.The nonlinear and linear inversion based on the particle swarm optimization and the non-negative least squares algorithm respectively are all show that the two earthquakes are thrusting and strike-slip earthquakes.The results of linear inversion show that both Meinong and Jiashian earthquakes are shallow blind faults,and the slipping of the two earthquakes are mainly located in 11-16 km and 9-14 km depth.The final magnitude of Jiashian and Meinong earthquakes are M_w 6.20 and M_w 6.37.This paper also obtained the Coulomb stress change model of the two earthquakes.The results show that the main region of the fault of Meinong earthquake showed positive stress and the stress value in some regions are above3.0 MPa after the Jiashian earthquake,which indicates that the Jiashian earthquake has an obvious accelerating effect on the occurrence of the Meinong earthquake.In addition,Hsinhua fault,Zouchen fault and Liuchia fault on southwestern Taiwan also showed positive stress.Especially,t Zouchen fault located on the west of the epicenter which has a high risk of earthquake.(3)This paper obtained the InSAR coseismic deformation fields of the 2009 L'Aquila earthquake and the three earthquakes in central Italy in 2016,and also the deformation near the epicenter of the October 30,2016 Mw 6.6 earthquake was obtained by pix offset tracking technology.The coseismic deformation results show that the four earthquakes are dominated by subsidence deformation.In this paper,two constant-strike and two variable-strike fault models are constructed.The results of the slip distribution based on the above models indicate that the faults of the four earthquakes are both normal fault and the seismic sources are shallow.The main slip regions of these earthquakes are located at 0-10 km depth.The magnitude of these four earthquakes are M_w 6.27,M_w6.27,M_w 6.19 and M_w 6.58.Based on the Coulomb stress change models,this paper finds that there has a significant trigger relationship between the August 24th,2016 earthquake and the October 26th,2016earthquake.After the four earthquakes,there is a seismic gap in the area of this sequence earthquake.The Montereale fault in the gap and the Barisciano fault located on the southeast of the Paganica fault have great earthquake risk.