Missing earthquakes detection and seismogenic structure analysis of the Xunwu ML 3.8 earthquake swarm
Matched filtering technology was used to detect missing seismic events in the Xunwu ML 3.8 earthquake swarm from November 2017 to April 2018.Then we determined P and S wave arrival times using seismic phase detection technology based on waveform cross correlation method,and used double-difference relocation method for relocation,The seismogenic structure of the swarm was analyzed by combining the distribution of the swarm,source mechanism solutions,and geological structures.The results show that a total of 36 missing earthquakes were detected in the Xunwu earthquake swarm,which is about 47％ of the catalogue of network,the catalog completeness is obviously improved for earthquakes below ML 1.2.After relocation,the distribution of earthquake swarm becomes more concentrated,spreads along the NE direction.The depth profile perpendicular to the dominant distribution of the earthquake swarm shows that the depth of the earthquake source gradually shallows from NW to SE,suggesting a possible seismic fault inclination towards NW.Based on the geological structures,relocated earthquakes and focal mechanisms,it is speculated that the seismogenic structure of this earthquake swarm is the Jitan-Liuche fault.
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