实时智能地震处理系统在2020年四川石渠M5.6地震序列中的应用

Application of real-time intelligent seismic processing system in the 2020’s M5.6 earthquake in Shiqu,Sichuan

实时智能地震处理系统(RISP)是一套基于深度学习技术的新型地震实时处理系统,于2021年6月在四川开始试运行。为了评估该系统在四川台网稀疏区域的地震检测和处理能力,笔者等采用RISP系统对2020年4月1日四川甘孜州石渠县发生的M5.6级地震序列进行了回溯性分析,获得了较为可靠的自动处理地震序列目录,并与人工目录进行了对比分析。震后10 d内,RISP系统自动处理获得了386个地震信号,地震数量是正式地震目录的1.98倍,匹配率为97.43%。分析显示,发震时刻偏差小于±1.0 s的地震占比71.05%,震中位置偏差小于10 km的地震占比96.31%,震级偏差小于±0.3级的地震占比99.47%。根据RISP系统检测地震序列分布特征和震源机制解,认为此次地震的发震断层为五道梁—长沙贡玛断裂北东侧的一条未发现的分支断层。研究结果表明,RISP系统的应用可以提升台网稀疏区域的地震检测能力,可快速产出地震序列目录,对大震应急、震后趋势判定和发震构造研究等具有重要意义。

Objectives:The Real-time Intelligent Seismic Processing(RISP)system is a new type of seismic real-time processing system based on deep learning technology,which was trialed on the Sichuan Network in June 2021.The purpose of this paper is to evaluate the reliability of the system’s output in the relatively sparse earthquake monitoring capabilities of western Sichuan,and to explore the feasibility of the system to automatically detect small earthquakes in this region.Methods:Taking the 2020’s M5.6 earthquake in Shiqu,Sichuan,as an example,the authors use RISP system to retrospectively analyze the earthquake sequence,and obtains a relatively reliable earthquake sequence catalog,which is compared with the manual catalogs.Results:Within 10 days after the main shock,386 automatic catalogs were automatically processed by the RISP system.The number of automatic catalogs is 1.98 times at of manual ones,and the matching rate is 97.43%.Compared with the manual catalogs,the 71.05%of origin time differences are less than±1.0 s,the 96.31%of epicentral differences are less than 10 km,and the 99.47%of magnitude differences are less than±0.3.Based on the distribution characteristics of the earthquake sequence detected by RISP and the focal mechanism solution,the seismogenic fault of this earthquake is considered to be an undiscovered branch fault on the northeast side of the Wudaoliang—Changsha Gongma fault.Conclusions:This study shows that the application of the RISP system can improve the seismic detection capabilities in sparse areas of the seismic network,and it can quickly produce a catalog of earthquake sequences,which is of great significance for major earthquake emergency response,post-earthquake trend determination,and seismogenic structure research.