评“紫坪铺水库造成孔隙弹性耦合变化及其对2008年汶川地震触发作用”二维模拟的局限性  

The 2D limitation of“Triggering effect of the Zipingpu Reservoir on the 2008 M_w7.9 Wenchuan,China,Earthquake due to poroelastic coupling”

作　　者：程惠红[1] 郑亮[1,2] 张贝[1] 孙玉军[3] 石耀霖[1] 

机构地区：[1]中国科学院计算地球动力学重点实验室,中国科学院大学,北京100049 [2]Institute of Geophysics, Swiss Federal Institute of Technology Zurich, Switzerland [3]中国地质科学院地质力学研究所,北京100081

出　　处：《地球物理学报》2015年第4期1458-1461,共4页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41404078);中国博士后科学基金面上资助项目(11910S192)联合资助

摘　　要：2014年10月《地球物理学报》出版的陶玮等（2014）“紫坪铺水库造成孔隙弹性耦合变化及其对2008年汶川地震触发作用”一文基于完全耦合孔隙弹性理论,采用二维有限单元法模拟了紫坪铺水库蓄水造成的库区应力场和孔隙压力场的变化.该文模拟计算原则和思路是正确的,但仍然采用二维模型是一个不足.真实三维模型中水库是有限的一定面积内的载荷;而二维计算模型,却把水库载荷作为无限长的带状载荷,夸大了水库的作用.如果考虑三维模型,该研究得到的震源处库仑应力增长2~25kPa的结论可能只能解读为0.7~8.0kPa.对于紫坪铺水库是否对汶川地震有触发作用,目前各个研究组估计的库仑应力变化恰好处在是否可以触发的边缘.取得进一步认识的关键有赖于对地下结构、状态和物性认识的突破性进展.The paper titled ＂Triggering effect of the Zipingpu Reservoir on the 2008 Mw7.9 Wenchuan, China, Earthquake due to poroelastic coupling＂ by Tao et al. （2014）, simulated the evolution of the pore pressure and stress changes due to the impoundment of Zipingpu reservoir using 2D finite element method, which is based on the fully coupled poroelastic theory. It is deficient to use 2D model, even though the principle and idea is correct. Actually, the load of reservoir is located within a certain area in 3D model. While, the 2D model means taking infinite linear loads instead of surface load, which may exaggerate the loading effect of reservoir. When considering the 3D, the result of the change of Coulomb failure stress of the hypocenter may be 0.7~8.0 kPa instead of the 2~25 kPa. Now, as for whether the Zipingpu Reservoir trigger the occurrence of Wenchuan Earthquake, the value of the Coulomb failure stress change calculated by each research group is just still on the edge of triggering. The keys to achieve further understanding depends on the more information of structure, state, and physical properties of the crust.

关 键 词：紫坪铺水库 汶川地震 二维模拟(2D) 孔隙弹性完全耦合 库仑应力变化(ΔCFS) 

分 类 号：P315[天文地球—地震学]