实时断层破裂尺度估计方法——以2016年M_(W)7.0熊本地震为例  

Real-Time Fault Rupture Scale Estimation Method-A Case Study of the 2016 M_(W) 7.0 Kumamoto Earthquake

作　　者：肖莹 卢建旗[1,2] 李山有 赵晏[1,2] XIAO Ying;LU Jianqi;LI Shanyou;ZHAO Yan(Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Key Laboratory of Earthquake Disaster Mitigation,Ministry of Emergency Management,Harbin 150080,China)

机构地区：[1]中国地震局工程力学研究所地震工程与工程振动重点实验室,黑龙江哈尔滨150080 [2]地震灾害防治应急管理部重点实验室,黑龙江哈尔滨150080

出　　处：《防灾减灾工程学报》2024年第6期1457-1464,共8页Journal of Disaster Prevention and Mitigation Engineering

基　　金：中国地震局工程力学研究所基本科研业务费专项资助项目(2018B02);国家重点研发计划项目(2018YFC1504004);国家自然科学基金(U2039209)资助。

摘　　要：实时估计地震震源参数并结合地震动预测方程进行地震动场预测,是地震预警系统中最常用且具有最高时效性的方法。对于中-大型地震而言,由于断层有限性效应的影响,获得准确的震源参数(震级、断层长度、断层走向以及单双侧破裂的比例系数)是影响该方法效能的关键因素。介绍一种针对大震的实时断层破裂尺度估计方法,包括主断层的破裂方向以及破裂长度,可用于实时地震动预测以及近实时地震影响场的绘制。通过最小化观测地震动参数值与加入断层模型参数后的理论预测值之间的误差函数,来确定最佳线源模型。通过实时追踪断层破裂情况,并对源模型进行校正,可以显著改善大震时传统点源模型对近断层区域的低估。同时,引入赤池信息准则可以自动判别何时使用线源模型,从而更加准确地预测地震动场。此方法作为传统预警方法面对大震时的补充,不仅不改变时效性,而且能够提高预测精度。使用2016年熊本M_(w)7.0地震对方法进行测试。结果表明,约在13 s左右,断层模型的角度开始收敛,在18 s后加入线源模型可以显著提高预测精度。这种方法能够快速准确地估计此次地震的震级和断层破裂参数,并具有很好的稳定性。Real-time estimation of earthquake source parameters combined with ground motion predic-tion equations for ground motion field prediction is the most commonly used and most time-efficient method in earthquake early warning systems.For medium to large earthquakes,obtaining accurate source parameters(magnitude,fault length,fault strike,and the proportion of unilateral or bilateral rupture)is a crucial factor affecting the effectiveness of this method,due to the influence of finite fault effect.A real-time fault rupture scale estimation method for large earthquakes was introduced,includ-ing the rupture direction and rupture length of the main fault,which can be used for real-time ground motion prediction and near-real-time seismic influence field mapping.The optimal line source model was determined by minimizing the error function between the observed ground motion parameters and the theoretical predicted values incorporating fault model parameters.By real-time tracking of fault rup-ture and correcting the source model,the underestimation of near-fault regions by traditional point source models during large earthquakes could be significantly improved.Furthermore,the introduc-tion of the Akaike Information Criterion could automatically determine when to use the line source model,so as to predict the ground motion field more accurately.As a supplement to traditional early warning methods for large earthquakes,this method not only maintained the timeliness but also im-proved the prediction accuracy.The method was tested in the 2016 Mw 7.0 Kumamoto earthquake.The results showed that at approximately 13 seconds,the angle of the fault model began to converge and adding the line source model after 18 seconds significantly improved the prediction accuracy.This method can rapidly and accurately estimate the magnitude and fault rupture parameters of the earth-quake and demonstrates good stability.

关 键 词：地震预警 地震动预测方程 破裂尺度估计 断层距 

分 类 号：TU443[建筑科学—岩土工程]