The spatio-temporal evolution characteristics of the MS6.0 Barkam earthquake sequence in Sichuan on June 10,2022
According to the China Earthquake Networks Center,at 00:03 on June 10,2022,local time,an earthquake with MS5.8(ML6.3)struck Barkam City(32.27°N,101.82°E),Aba Prefecture,Sichuan Province,with a focal depth of 10 km.Subsequently,at 01:28 local time,another MS6.0(ML6.5)earthquake occurred in the same location(32.25°N,101.82°E),with a focal depth of 13 km.These two earthquakes were located in the southeast part of the Bayan Har block,approximately two kilometers apart.According to the definition of earth-quake sequence type,the magnitude difference between the two earthquakes ΔM=0.2 consti-tutes a swarm type earthquake,which is hereinafter referred to as"MS6.0 Barkam earthquake swarm".The MS6.0 Barkam earthquake swarm exhibited numerous minor earthquakes,up un-til 23:00 on June 30,2022,a total of 4 821 earthquakes of magnitude 0 and above were recor-ded,including seven earthquakes with magnitude ranging from MS3.0 to MS3.9,three earth-quakes with magnitude ranging from MS4.0 to MS4.9,two earthquakes with magnitude ran-ging from MS5.0 to MS5.9,and one MS6.0 earthquake.The largest aftershock recorded was an earthquake with MS5.2(ML5.6)at 03:27 local time on June 10.Considering the significant event of an earthquake with MS5.8 preceding the occurrence of the main shock with MS6.0,it is important to investigate the characteristics of the MS5.8 earthquake sequence as a foreshock and the sequence features before and after the main shock.Existing seismological methods in-dicate that earthquake sequences can intuitively reflect differences in tectonic stress fields,seis-mic structures,and the seismogenic environment medium.Moreover,the rupturing properties of the main shock often influence the evolution of aftershock sequences.This study utilizes seis-mic data from the Sichuan regional seismic network,based on parameters such as the b-value and p-value of the sequence,in combination with regional structure and focal mechanism solu-tion parameters of the strong aftershock,to investigate the spatio-temporal evolution character-istics of the Barkam MS6.0 earthquake swarm sequence and to explore the sequence evolution characteristics before major earthquakes in Barkam.
the MS6.0 Barkam earthquake sequenceSonggang faultsequence parameterforeshock
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