利用球形地球位错理论研究日本M_(W)9.0地震引起的稳态变形与库仑应力变化  

Steady-state deformation and Coulomb failure stress change induced by the 2011 Tohoku-Oki M_(W)9.0 earthquake based on spherical dislocation theory

作　　者：陈伟 刘泰[1] 唐河 佘雅文[1] 付广裕 CHEN Wei;LIU Tai;TANG He;SHE YaWen;FU GuangYu(Key Laboratory of Earthquake Forecast,Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China;Key Laboratory of Computational Geodynamics,University of Chinese Academy of Sciences,Beijing 100049,China;School of Geophysics and Information Technology,China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国地震局地震预测重点实验室(地震预测研究所),北京100036 [2]中国科学院大学计算地球动力学重点实验室,北京100049 [3]中国地质大学(北京)地球物理与信息技术学院,北京100083

出　　处：《地球物理学报》2022年第12期4760-4774,共15页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41874003,42104086,42274008);中国地震局地震预测研究所基本科研业务费专项(2021IEF0504,2020IEF0502)联合资助.

摘　　要：稳态地震变形是指由地震引起的、超长时间尺度内震后黏弹性松弛效应的累加,通过对稳态地震变形的研究,可以研究大地震导致的地球总体震后形变场,有利于分析周边地区对该地震的极限响应.本文首先利用球形地球地震位错理论,计算了日本M_(W)9.0地震在日本列岛和中国东部地区产生的稳态水平位移.结果表明,日本M_(W)9.0地震在日本本岛引起的稳态水平位移最大可达到8 m,大体上是同震水平位移的两倍;在中国东北地区产生的稳态水平位移最大值超过0.8 m,在华北地区产生的稳态水平位移最大值为0.5 m左右,是同震水平位移的30~40倍.接着,本文根据前人研究成果,结合地质资料,建立了中国东北和华北地区15条主要断裂带的几何与滑动构造模型,然后利用球形地球位错理论计算了日本M_(W)9.0地震在上述断裂带上引起的同震与稳态库仑应力变化.结果表明,该强震在中国东北和华北地区主要断裂带上引起的同震库仑应力变化均不超过1 kPa;稳态库仑应力变化显著超过同震结果,但除了依兰—伊通断裂带北段和嫩江断裂带南段的一部分以外,其他断裂带上的稳态库仑应力变化均未超过10 kPa这个地震触发阈值.因此日本M_(W)9.0地震对中国东北和华北地区地震危险性影响有限,不会显著改变区内主要断裂带的应力状态和地震活动性.Steady-state seismic deformation refers to the accumulation of viscoelastic relaxation effects caused by earthquakes on ultra-long time scales.Through the study of steady-state seismic deformation,the overall postseismic deformation field of the earth can be studied,which is beneficial to analyze the ultimate response of the surrounding area to the earthquake.In this paper,we first calculate the steady-state horizontal displacements produced by the 2011 Tohoku-Oki M_(W)9.0 earthquake in Japan and eastern China using spherical earth dislocation theory.The results show that the steady-state horizontal displacements caused by the great earthquake on the main island of Japan will reach a maximum of 8 m,which is roughly twice the coseismic horizontal displacements.The steady-state horizontal displacements in Northeast China will exceed 0.8 m,and in North China,the steady-state horizontal displacements will reach about 0.5 m,which is 30~40 times the co-seismic horizontal displacements.Then,the geometric and sliding tectonic models of 15 major fault zones in Northeast and North China were established based on previous research results and geological data.And then the coseismic and steady-state Coulomb failure stress changes caused by the 2011 Tohoku-Oki M_(W)9.0 earthquake on the above-mentioned fault zones were calculated using the spherical earth dislocation theory.The results show that the coseismic Coulomb failure stress changes induced by the great earthquake on the main fault zones in Northeast and North China do not exceed 1 kPa.As a whole the steady-state Coulomb failure stress changes significantly exceed the coseismic results.The steady-state Coulomb failure stress changes on the faults do not exceed the seismic trigger threshold of 10 kPa,except for the northern part of the Yilan—Yitong fault and the southern part of the Nenjiang fault.Therefore,the 2011 Tohoku-Oki M_(W)9.0 earthquake has little impact on the seismic hazard of Northeast and North China,and change slightly the stress state and seismicity of

关 键 词：日本M_(W)9.0地震 球形地球位错理论 稳态变形 库仑应力变化 地震危险性 

分 类 号：P315[天文地球—地震学]