川滇块体东边界断裂带应力演化特征及地震危险性数值  

Stress Evolution Characteristics and Numerical Analysis of the Seismic Hazard of the Eastern Boundary Fault Zone of the Sichuan-Yunnan Block

作　　者：李彦欣 董培育[1,2] 赵斌 LI Yanxin;DONG Peiyu;ZHAO Bin(Institute of Seismology,CEA,40 Hongshance Road,Wuhan 430071,China;Key Laboratory of Earthquake Geodesy,CEA,40 Hongshance Road,Wuhan 430071,China)

机构地区：[1]中国地震局地震研究所,武汉市430071 [2]中国地震局地震大地测量重点实验室,武汉市430071

出　　处：《大地测量与地球动力学》2024年第4期341-349,共9页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(42174113);中国地震局地震科技星火计划(XH21020)。

摘　　要：建立川滇块体东边界及龙门山断裂带区域三维粘弹性有限元模型,以GNSS速度场为约束,计算区域内主要断裂带长期平均构造应力积累速率;并根据历史地震破裂滑动模型,计算其对鲜水河断裂带、龙门山断裂带等造成的同震和震后库仑应力变化,从而得到研究区域主要断裂带总应力演化结果。研究表明,鲜水河断裂带、大凉山断裂带南段以及理塘断裂带的构造应力积累速率较高,达到1.0~1.5 kPa/a。2022年泸定MS6.8地震破裂区在一个地震复发周期内的构造应力积累量约为0.177 MPa,而历史强震产生的库仑应力加载量为0.07 MPa,二者共同导致了泸定地震的发生。此外,安宁河断裂带地震空区在前次地震离逝时间(约487 a)内的总应力积累量约为0.3 MPa,大凉山断裂带南段以及理塘断裂带历史地震离逝时间均为千年左右,总应力积累量>1.0 MPa,可能有较大的地震活动潜力。We construct a three-dimensional viscoelastic finite element model of the eastern boundary fault zone of the Sichuan-Yunnan block.We calculate long-term average tectonic stress loading rate of the main faults with GNSS observation data as a constraint.According to the historical earthquake rupture models,we calculate the co-and post-seismic Coulomb stress changes in Xianshuihe fault zone,Longmenshan fault zone and so on.Then,we obtain the total stress evolution of the main fault zone in the study area.The results show that the tectonic stress loading rate on Xianshuihe fault zone,the southern section of Daliangshan fault zone,and Litang fault zone are high,which can reach 1.0 to 1.5 kPa/a.In addition,the tectonic stress accumulation in the 2022 Luding M S6.8 earthquake rupture area is about 0.177 MPa during the seismic recurrence cycle,and the historical events produced 0.07 MPa stress loading.The two stress accumulations together led to the Luding earthquake’s occurrence.In addition,the total stress accumulation on the Anninghe fault zone seismic gap area since the occurrence of the previous event(about 487 years ago)is about 0.3 MPa.The last rupture events occurred about 1000 years ago in the southern section of Daliangshan fault zone and Litang fault zone,and the total stress accumulation in the seismic recurrence cycle is more than 1.0 MPa,which may indicate that these areas have greater seismic activity potential.

关 键 词：川滇块体东边界断裂带 数值模拟 构造应力加载 库仑应力变化 

分 类 号：P315[天文地球—地震学]