青藏高原及邻区未来地震活动性趋势数值分析  

Numerical analysis of the future seismic hazards in the Tibetan Plateau and its surrounding area

作　　者：董培育[1,2] 石耀霖 程惠红 乔学军 DONG PeiYu;SHI YaoLin;CHENG HuiHong;QIAO XueJun(Key Laboratory of Earthquake Geodesy,Institute of Seismology,China Earthquake Administration,Wuhan 430071,China;Key Laboratory of Computational Geodynamics,Chinese Academy of Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国地震局地震研究所,地震大地测量重点实验室,武汉430071 [2]中国科学院大学,中国科学院计算地球动力学重点实验室,北京100049

出　　处：《地球物理学报》2020年第3期1155-1169,共15页Chinese Journal of Geophysics

基　　金：国家自然科学基金（41704101）,国家自然科学基金重大项目（41590865）,国家自然科学基金面上项目（41774106）共同资助;国家自然科学基金-地震局地震科学联合基金（U1839207）

摘　　要：区域中长期地震危险性数值分析研究,需要对其初始构造应力场有所了解,但目前以及未来一段时期内仍无法直接观测到深部孕震层区域的应力场状况.本文首先基于岩石库仑-摩尔破裂准则,利用青藏高原及邻区百年历史范围内的强震信息,来反演估算该区域的初始应力场.然后,考虑区域构造应力加载及强震造成的应力扰动共同作用,重现了历史强震的发展过程.然而对于初始应力场的反演估算,本文仅能给出区域其上下限的极限值,并不能唯一确定.因此,采用Monte Carlo随机法,进行大量独立的随机试验计算,生成数千种有差异的区域初始应力场模型,且保证每种模型都能令历史强震有序发生,但未来应力场演化过程不尽相同.最后,将数千种模型在未来时间段内的危险性预测结果集成为数理统计结果,据此给出了区域未来的地震危险性概率分布图.初步结果显示未来强震危险性概率较高地区集中在巴颜喀拉块体边界及鲜水河断裂带地区.It′s necessary to know the regional initial tectonic stress for the numerical analysis of the medium-and long-term seismic hazard,however,it is still not possible to directly observe the tectonic stress data in the deep seismogenic zone at present.In this study,firstly,we inversely estimated a possible regional initial stress in the Tibetan Plateau and its surrounding area,based on the Coulomb-Mohr rupture criterion and the regional historical strong earthquakes information.Secondly,we orderly reproduced the historical strong earthquakes occurred in this region,by using the calculated tectonic loading stress rate and stress disturbance value caused by the historical strong earthquakes.However,in this study,the initial tectonic stress value still can′t be accurately determined,we can only get the constrained limit value,which means the estimated initial stress is only a possible value in the reasonable range.Therefore,we generated a large number of independent random different possible initial values within the reasonable range by using the Monte Carlo random method,which all can ensure the historical strong earthquakes orderly occur,and the stress evolution will be different in the future.Finally,we investigated the future seismic hazard situation of the thousands of models with the mathematical method.And then,we got the probability distribution map of possible future seismic risk in the region.Our preliminary results show that there is a higher probability of seismic risk in the Bayan Har Block boundary and the Xianshuihe fault zone.

关 键 词：青藏高原 有限元数值模拟 构造应力场演化 地震危险性概率预报 

分 类 号：P313[天文地球—固体地球物理学] P315[天文地球—地球物理学]