西南区域自动地震速报系统定位结果评估

Evaluation of Location Results of Southwestern Regional Automatic Earthquake Information Release System

对比分析2009年7月1日~2017年12月31日西南区域自动地震速报系统产出的1467个地震定位结果与全国统一编目目录,结果显示:①自动速报的平均用时为70s;96.37%的地震发震时刻偏差小于5s;91.64%的地震震中定位误差小于20km;99.52%的地震深度偏差小于20km;②当3.0≤M<4.0时,震级匹配最好;当M<3.0及4.0≤M<4.5时,震级偏差小于0.3;当M≥4.5时,自动速报震级小于统一编目震级,且震级越大,偏差越大;当M≥6.0时,震级偏差明显增大,自动速报震级不具可靠性;③发震时刻、震中位置、震级、深度等偏差较大的问题,主要是台站分布不合理且没有近台、大震尾波的干扰、同一地区短时间震群事件中的余震较多等因素造成的。此外,对系统的漏报、误报情况进行了分析,并对区域自动地震速报系统的完善与整合提出了建议。

We compared the location results based on the southwestern regional automatic earthquake information release system with officially published earthquake catalog from July 1,2009 to December 31,2017.The results shows that:(1)The average time used for automatic reporting is 70s;96.37%of the origin time error is less than 5s;91.64%of the horizontal error is smaller than 20km;99.52%of the depth error is not more than 20km.(2)When 3.0≤M<4.0,the magnitude match is best.When M<3.0 and 4.0≤M<4.5,the magnitude error is less than 0.3,When M≥4.5,the magnitude of the automatic earthquake information release system is smaller than that of the officially published earthquake catalog,and the larger the magnitude is,the larger the error is.When M≥6.0,the magnitude error is obviously increased,the magnitude of automatic earthquake information release system is not reliable.(3)The errors in earthquake origin time,epic central location,magnitude,and depth are basically caused by unreasonable distribution of stations,lack of interference from near-stations,large-sound wake waves,and more aftershocks in short-term earthquake swarm events in the same area.We also analyzed and discussed the issue of false alarm a missing report for the release system,and some suggestions for the improvement and integration of the automatic earthquake information release system were put forward.