基于数值模拟和地震活动性统计的混合地震预测:在中国地震科学实验场的应用  

A hybrid method of earthquake forecasting based on numerical simulation and seismicity statistics:An application to China Seismic Experimental Site

作　　者：姚琪 王辉[1] 刘杰[2] 王海涛 张微 杨文[2] 赵静[2] 姜祥华 YAO Qi;WANG Hui;LIU Jie;WANG HaiTao;ZHANG Wei;YANG Wen;ZHAO Jing;JIANG XiangHua(Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China;China Earthquake Networks Center,Beijing 100039,China;School of Software Technology,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]中国地震局地震预测研究所,北京100036 [2]中国地震台网中心,北京100039 [3]浙江大学软件学院,杭州310027

出　　处：《地球物理学报》2023年第10期4162-4175,共14页Chinese Journal of Geophysics

基　　金：地震科学联合基金(U2039207);科技部重点研发专项(2021YFC3000605);国家自然科学基金(42274131)资助。

摘　　要：地震数值预测是近年来最为前沿的科学研究问题之一,但是大部分地震数值预测的探索都受困于数值模拟步长的问题.本文引入混合预测方法,探索了较短预测时长的地震数值预测方法,并在中国地震科学实验场区中进行应用.该混合预测方法主要建立在活动块体理论和构造力学分析的基础上,利用数值模拟推测未来长时间的应力变化量,并引入上一次7级地震之后数十年间,中等强度地震同震应力的影响,最后通过重分类和加权,在应力变化量上叠加年尺度小地震活动异常的统计,从而实现区域地震危险程度的混合评估.基于该方法,我们将地震数值预测的预测时间尺度缩短到年尺度,以年为单位滚动预测了中国地震科学实验场自2021—2030年或更长时间段内可能出现中强地震的区域.2022年芦山6.1级地震、2021年漾濞6.4级地震、2021年泸州6.0级地震和2022年泸定6.8级地震均发生在危险性较高的区域,而2022年马尔康6.0级地震则不在预测区域内.本文展示的混合预测尝试为地震数值预测研究提供了一个可供参考的例证,也为解决数值预测步长控制难的问题提供了一个可能的探索途径.Earthquake forecasting using numerical methods has recently been given much attention.Most previous explorations were trapped by calculation time steps,which generally refer to a long time.In this paper,a new numerical forecasting method with a shorter duration time is explored and applied to China Seismic Experimental Site(CSES)based on a hybrid method.Considering active block theory and structural mechanical analysis,we used a three-dimensional finite element simulation to calculate the long-term stress variation.Then the co-seismic stress released by moderate earthquakes,which occurred after the last big earthquake for decades,was superimposed on local regions.The annual scale's seismic statistic for small earthquakes was also overlaid by reclassification and weighted calculation.Therefore,the duration of earthquake forecasting is shortened by involving an annual scale.We illustrated the graded seismic risk on southeastern margin of the Sichuan-Yunnan border from 2021 to 2030.The 2022 Lushan M_(S)6.1 earthquake,the 2021 Yangbi M_(S)6.4 earthquake,the 2021 Luzhou M_(S)6.0 earthquake,and the 2022 Luding M_(S)6.8 earthquake occurred in the high-risk area,but the 2022 Barkam M_(S)6.0 earthquake occurred in the low-risk region.The hybrid method presented in this paper solves the length of calculation step in numerical simulation applied to earthquake forecasting.It includes both physics-based numerical simulation and statistical seismological analysis.Furthermore,it provides a possible exploration approach for numerical earthquake forecasting and its application.

关 键 词：地震数值预测 混合方法 数值模拟 核密度估计 2022年芦山M_(S)6.1地震 2022年马尔康M_(S)6.0地震 

分 类 号：P315[天文地球—地震学]