基于地震P波双参数阈值的高速铁路Ⅰ级地震警报预测方法

摘要

In order to improve the timeliness of earthquake emergency response for high speed railway and meet the requirements for effectiveness,the prediction method of first-level earthquake warning for high speed railway was studied using the thresholds of the predominant period τc and the peak amplitude of vertical displacement Pd from P-wave arrivals.The linear relationships were derived between τc and earthquake magnitude M and between Pd and the earthquake acceleration PGA from the time windows of 1 s,2 s and 3 s after P-wave arrivals using Japanese K-net strong ground motion data.The method called "four levels prediction method" of the first-level earthquake warning for high speed railway was proposed by using the threshold of τc corresponding to M=6 and the threshold of Pd corresponding to PGA=40 cm · s-2 at 3 time windows of P-wave based on these two statistical relationships mentioned above.Level 3 is defined as the prediction standard for the first-level earthquake warning of high speed railway.The effectiveness and timeliness of the "four levels prediction method" were analyzed using the strong ground motion data recorded by the K-net stations along the Kyushu Shinkansen in Kumamoto earthquake (Mj =6.5) on April 14,2016.Results show that the method can accurately predict first-level earthquake warning after the first 1 s P-wave arrival in the station KMM006 which is closest to the source of the earthquake.Meanwhile,this alert time is 3.34 s and 4.84 s earlier than the Kyushu Shinkansen derailment time and the Japan Meteorological Agency (JMA) Earthquake Early Warning (EEW) issued time,respectively.The proposed method can meet the needs for the development of earthquake monitoring and early warning system for high speed railway.%以提升高速铁路地震紧急处置的时效性并满足有效性要求为目标,研究基于地震P波卓越周期τc阈值和最大竖向位移Pd阈值的高速铁路Ⅰ级地震警报预测方法.利用日本K-net强震数据,分别统计P波触发后1,2,3 s时间窗下τc与震级M的线性关系和Pd与地震加速度PGA的线性关系,基于这2种统计关系计算得到P波3个时间窗下震级M=6时对应的τc的阈值和PGA=40 cm·s-2时对应的Pd的阈值,在此基础上,建立高速铁路Ⅰ级地震警报“4等级预测方法”,明确等级3为达到高速铁路Ⅰ级地震警报的预测标准.采用2016年4月14日熊本6.5级地震时九州新干线沿线K-net强震台站的数据,分析“4等级预测方法”的有效性与时效性.结果表明:该方法可以在最接近震源的KMM006台站P波触发后1 s准确地预测出Ⅰ级地震警报,并较九州新干线脱轨时刻和气象厅紧急地震速报发布时刻分别提前了3.34和4.84 s,能够满足高速铁路地震监测预警系统发展的需要.