川滇地区地壳应变能密度变化率与强震复发间隔的数值模拟  

THE NUMERICAL SIMULATION OF THE STRAIN ENERGY DENSITY CHANGING RATE AND STRONG EARTHQUAKE RECURRENCE INTERVAL OF THE SICHUAN-YUNNAN BLOCK

作　　者：祝爱玉[1] 张东宁[1] 蒋长胜[1] 黎明[1] 

机构地区：[1]中国地震局地球物理研究所,北京100081

出　　处：《地震地质》2015年第3期906-927,共22页Seismology and Geology

基　　金：国家科技支撑计划项目(2012BAK15B01);中国地震局地震行业科研专项(201008001)共同资助

摘　　要：以最新的川滇地区深部构造成像为基础,以构造应力场、GPS观测和断裂带活动速率为约束,建立了川滇地区的3维黏弹性有限元模型,通过数值模拟计算讨论青藏高原高海拔地形蓄积的重力位能、区内主要活动断裂带的错动速率、由地震波速度计算出来的各地块的介质弹性参数以及岩石、介质蠕变性质差异对川滇地区地壳现今构造运动的影响。模拟计算出研究区域内各主要活动地块和主要活动断裂带的应变能密度积累速率,并探讨了应变能密度积累速率与强震复发间隔的关系,对模拟结果和地质观测方法得到的结果进行了比较分析。模拟结果显示:青藏高原及文中研究区域内高海拔地形蓄积的重力位能和块体间的相互作用是控制区内主要活动断裂现今滑动速率、各Ⅱ级活动块体运动性质和地壳内应变能积累速率的主要动力学因素。Based on the deep structure imaging of Sichuan-Yunnan region, a three-dimensional viscoelastic finite element model is established, and the simulation is constrained by tectonic stress field, Global Positioning System（ GPS） observations and fault activities. In this paper, we focus on the discussion about the effect of gravitational potential energy of high altitude terrain, the slip rate of major active faults, the difference of elastic parameters and the creep feature of the rock medium on the distribution characteristics of strain energy density. We obtain the strong earthquake recurrence interval of the major active block which is reduced by strain energy density and the main active faults, and also we compare the simulated results and geological observations. The simulation results show that the gravitational potential energy accumulated by the high altitude terrain and the interaction between blocks are the main geodynamical factors, which control the active fault slip rate, the activity of the second class block, and the recurrence interval of strong earthquakes in the Yunnan-Sichuan area.

关 键 词：川滇地区 有限元数值模拟 应变能密度变化率 强震复发间隔 

分 类 号：P315.8[天文地球—地震学]