Microearthquake Detection and Its Tectonic Implications in the Eastern Segment of the East Kunlun Fault Zone
To comprehensively analyze the seismic activity of the East Kunlun Fault Zone from 2009 to 2018,we developed a proced-ure encompassing microearthquake detection,seismic denoising,seismic phase picking,and seismic location to construct a seismic cata-log.We collected continuous waveforms recorded by 20 stations in the eastern segment of the East Kunlun Fault Zone from January 2009 to December 2018.From the 3 198 seismic events listed in the China Earthquake Networks Center(CENC)catalog,we selected 1200 events with clear seismic phases and high signal-to-noise ratios as template events.Using the Graphics Processing Unit-based Match and Locate(GPU-M&L)method,we detected a total of 13,318 earthquake events,including the template events,which is roughly 4.2 times the number of events in the CENC catalog.Next,we employed the neural network-based seismic waveform denois-ing technique(DeepDenoiser)to extract seismic signals from the noise.By examining the time-domain and frequency-domain charac-teristics of noise and seismic signals,we further identified and confirmed 7514 seismic events,approximately 2.3 times the number re-ported by the CENC.The complete magnitude of the detected catalog decreased from ML 1.5,as given by the CENC,to ML 0.9 in this study.Subsequently,we applied the deep neural network-based seismic arrival-time picking algorithm(PhaseNet)to pick the seismic phases.Finally,using the double-difference localization method(hypoDD),we finely located 7247 events.The results show that earth-quakes in the eastern segment of the East Kunlun Fault Zone are linearly distributed or clustered,with focal depths predominantly ran-ging from 0 to 15 km.East of 101°E,the spatial distribution of earthquakes mainly spreads southeastward along the Awancang Fault Zone.Additionally,our results indicate a possible seismic gap in the Maqin-Maqu segment.This study provides an important database for further research on seismic activity and deep seismogenic faults in the eastern segment of the East Kunlun Fault Zone.
The East Kunlun Fault ZoneMicroearthquake detectionMatch and locate methodSeismic denoiseDouble dif-ference location
万方数据
维普
