模拟PLUM方法在2021年日本福岛县近海M7.3级地震中的表现

Simulation of the performance of PLUM method in the 2021 M 7.3 earthquake off the coast of Fukushima Prefecture,Japan

2021年2月13日晚,日本福岛县近海发生M 7.3级地震,产生强烈振动,此次地震被认为是“3.11”地震的余震。首先介绍了PLUM方法的原理及日本气象厅地震预警系统对于PLUM方法的应用,评述了JMA地震预警结果。通过模拟PLUM方法在此次地震中的表现,由预测精度和有效预警时间两个指标来评估该方法的性能,并与日本气象厅发布的预警信息对比。模拟结果显示:受限于地震数据以及PLUM方法本身的原理,在震后第24 s发出第一次警报,不及使用P波预警与PLUM相结合的JMA地震预警系统及时。在地震前期0~40 s处于烈度剧烈上升阶段,预测精度较差;40 s之后的预测结果较为准确,预测精度高达100%。PLUM方法可以有效克服点-源模型中的弊端,特别是在多个地震同时发生的情况下预警效果良好,将PLUM方法纳入我国地震预警系统可以有效提高预警能力。

On the evening of February 13,2021,an earthquake with a magnitude of M 7.3 struck off the coast of Fukushima Prefecture,Japan,causing strong shaking.This earthquake is believed to be an aftershock of the“3.11”earthquake.In this paper,the principle of PLUM method and the application of PLUM method by Japan Meteorological Agency earthquake early warning system are introduced firstly,and the results of JMA earthquake early warning are reviewed.By simulating the performance of PLUM method in this earthquake,the prediction accuracy and effective warning time were used to evaluate the performance of the method,and compared with the warning information released by the Japan Meteorological Agency.The simulation results show that due to the limitation of seismic data and the principle of PLUM method itself,the first alarm issued 24 s after the earthquake is not timely enough as the JMA earthquake warning system combining P-wave warning and PLUM.In the early 0-40 s of the earthquake,the intensity rises sharply,and the prediction accuracy is poor.After 40 s,the prediction result is more accurate,and the prediction accuracy is as high as 100%.PLUM method can effectively overcome the disadvantages of point-source model,especially in the case of simultaneous occurrence of multiple earthquakes,the warning effect is good,and the application of PLUM method into the earthquake early warning system in China can effectively improve the ability of earthquake early warning.