A high-resolution seismic catalog for the 2021 Ms6.4/Mw6.1 Yangbi earthquake sequence,Yunnan,China:Application of AI picker and matched filter

• 作者: Yijian Zhou Abhijit Ghosh Lihua Fang Han Yue Shiyong Zhou Youjin Su
• 来源期刊: 地震学报（英文版）
• 年，卷（期）: 2021,（5）
• 页码范围: 390-398
• 页数: 9页
• 语种: 英文
• DOI: 10.29382/eqs-2021-0031

摘要

We present a high-resolution seismic catalog for the 2021 Ms6.4/Mw6.1 Yangbi sequence.The catalog has a time range of 2021-05-01 to 2021-05-28,and contains～8,000 well located events.It captures the features of the whole foreshock sequence and the early aftershocks.We designed a detection strategy incorporating both an artificial intelligent(AI)picker and a matched filter algorithm.Here,we adopt a hybrid AI method incorporating convolutional and recurrent neural network(CNN&RNN)for event detection and phase picking respectively(i.e.CERP),a light-weight AI picker that can be trained with small volume of data.CERP is first trained with detections from a STA/LTA and Kurtosis-based method called PAL,and then construct a rather complete template set of～4,000 events.Finally,the matched filter algorithm MESS augments the initial detections and measures differential travel times with cross-correlation,which finally results in precise relocation.This process gives 9,026 detections,among which 7,943 events can be well relocated.The catalog shows as expected power-law distribution of frequency magnitude and reveals detailed pattern of seismicity evolution.The main features are:(1)the foreshock sequence images simple fault geometry with consistent strike,but also show a variable event depth along strike;(2)the mainshock ruptures the same fault of the foreshock sequence and activate conjugate faults further to the southeast;(3)complex seismicity are developed in the post-seismic period,indicating complex triggering mechanisms.Thus,our catalog provides a reliable basis for further investigations,such as b-value studies,rupture process,and triggering relations.