On September 5,2022,a M6.8 earthquake occurred in Luding county,Sichuan Province.The epicenter is located at the southeastern end of the Xianshuihe fault.The preliminary results of field geological investigation show that no obvious surface rupture caused in this earthquake.We obtain the static horizontal coseismic displacements within 90 km of the epicenter at 31 survey-mode and continuously operated GNSS stations.The deformation pattern measured by GNSS is agreement with the left-lateral strike slip faulting mechanism.The maximum horizontal coseismic displacement observed by GNSS reaches 23 cm,and the GNSS stations within 50 km of the epicenter records coseismic offsets generally over 1 cm.The optimal coseismic slip model derived from GNSS data shows that the surface rupture mainly concentrated between Moxi town to Tianwan township.The coseismic slip concentrates at depths of 2～8 km,with the maximum slip of 1.96 m.The estimated seismic moment is 9.25 × 1018 N·m,corresponding to Mw6.6.The earthquake has enhanced the Coulomb stress on the fault planes around the periphery of the source rupture area,and a large fraction of aftershocks occurred in the region where Coulomb stress increased.Considering the interseismic coupling ratio,historical earthquake ruptures and Coulomb stress variations,it is worth paying more attentions on seismic hazards of Anninghe fault,Daliangshan fault and Kangding-Moxi segment of the Xianshuihe fault in near future.
维普
万方数据