Data products of the 2023 MS 6.2 earthquake in Jishishan,Gansu Province,China
On December 18,2023,an MS 6.2 earthquake occurred in Jishishan County,Gansu Province,on the northeastern edge of the Qinghai-Xizang Plateau.After the earthquake,China Earthquake Networks Center(CENC)started the emergency response immediately,and the National Seismic Network Center carried out the output of rapid seismic data products to provide basic materials for the study of seismogenic tectonics and the assessment of seismic hazard.Based on the data from the China Seismic Networks,the gCAP method is used to obtain the focal mechanism solution of the mainshock,which shows that the earthquake is a predominantly thrust-type event with a left-lateral component,and the centroid depth is 11 km.The double-difference location method is used to relocate the Jishishan mainshock and the sequence of 623 aftershocks within 27 days,and the result shows that the location of the mainshock is(35.75°N,102.83°E),with a depth of 14 km,while the aftershock sequence spreads in the direction of NNW,with a length of about 18 km,whose dominant distribution is of 5-17 km in depths,with a slightly eastward-dipping trend on the fault plane.In addition,based on the results of the location and focal mechanism obtained in this study,the Coulomb stress distribution at different depths of this earthquake is calculated by using the PSGRN/PSCMP code,and the result shows that the occurrence of the mainshock causes the source area a stress unloading status.Finally,the instrumental intensity of this earthquake is calculated with the data from the China Earthquake Early Warning Network(CEWN),and shows that the maximum intensity value isⅨ,concentrated in a small region and mainly focused on the NNW direction.Combined with the neighboring geological structure,the MS 6.2 event in Jishishan,Gansu is considered to be an uplift-type earthquake with a left-later slip component.
Jishishan MS 6.2 earthquakerelocationfocal mechanismCoulomb stressinstrumental intensity
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