Aftershock sequence relocation of the MS6.8 earthquake on September 5,2022,in Luding,Sichuan Province
Zhang Shengxia
Ma Xiaomei
Zhang Fengxue
Abstract：On September 5,2022,an MS6.8 earthquake,with a meizoseismal intensity of IX,struck Luding,Sichuan Province,causing severe casualties and economic losses.In this study,we applied the double-difference al-gorithm(HypoDD)to relocate the mainshock and aftershock sequences within a 25-day period.Precise hypocen-tral and spatial distributions were determined,with the hypocentral location of the mainshock recorded at(29.59°N,102.10°E)and a depth of 14.3 km.By analyzing the spatial and temporal distribution of aftershocks and the depth profile of the Luding MS6.8 earthquake,we estimate that the aftershock fracture zone spans approximately 65 km long and 10-20 km wide.Three distinct aftershock clusters formed along the northern,central,and southern sec-tions of the fault,with focal depths gradually deepening from north to south.Further analysis of the seismic struc-ture revealed that the mainshock and aftershocks were distributed unilaterally along the Xianshuihe fault,specifi-cally along the Moxi segment.This earthquake also activated a secondary,previously hidden fault near Gongga Mountain.Additionally,we examined the seismogenic relationships between the MS6.8 Luding earthquake and oth-er recent seismic events,including the 2022 MS6.1 Lushan earthquake,the 2013 MS7.0 Lushan earthquake,and the 2014 MS6.3 Kangding earthquake.Using the IDS system,we inverted the hypocentral movement characteris-tics and obtained the basic parameters of the mainshock rupture,finding a strong correlation between the rupture process and the spatial distribution of aftershocks.
Keywords：Luding earthquakeaftershock sequencedouble difference locationhypocenter location
Publication Date：2025-09-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 563-572 )