大震地震序列自动地震速报结果分析——以云南漾濞6.4级和青海玛多7.4级地震为例

Analysis of Results from the Automatic Earthquake Monitoring System for Large Earthquake Sequence——A Case Study of Yangbi,Yunnan and Maduo,Qinghai Earthquakes

根据国家台网中心自动地震速报系统在云南漾濞和青海玛多2个地区的台网监测能力,选取2个地区2021年5月18—29日的地震序列,对自动地震速报系统进行性能分析。国家台网中心自动地震速报系统基本实现1min内的单路自动地震速报信息初次产出,根据地震台网密度的不同,产出时间从30~60s不等。与地震编目结果相比,云南漾濞地震序列震中位置偏差较小,青海玛多地震序列震中位置偏差较大,2个地震序列震级偏差不大。青海玛多地震序列震中位置偏差较大的原因是该区域台站稀少且空隙角较大。自动地震速报系统存在少量的漏报地震,与系统定位时信噪比较低、台站空隙角较大及多个地震混叠在一起有关。

We selected two earthquake sequences based on the monitoring capabilities of the nation automatic earthquake information release system in Yangbi of Yunnan Province and Maduo of Qinghai Province,from May 18,2021 to May 29,2021,to analyze the performance of the system in the earthquake sequence.The nation automatic earthquake information release system basically realizes the first output of single-channel automatic earthquake information within 1 minute,and the output time varies from 30 seconds to 60 seconds according to the density of the station network.Compared with the earthquake cataloguing results,the deviation of the earthquake epicenter location of the earthquake sequence in Yangbi,Yunnan was small,while the deviation of the epicenter location of the Qinghai Maduo earthquake sequence was relatively large.However,the deviation of magnitude of both earthquake sequences was not large.The large deviation of the epicenter location may be due to the scarcity of stations in the area,lack of nearby stations and the large gap angles between stations.There were a small number of missed earthquakes in the automatic earthquake information release system,which is probably related to the low signal-tonoise ratio of the system during positioning,the large gap angle of the station,and the aliasing of multiple earthquakes.