龙门山断裂带深部构造变形的粘弹性模拟分析  

Viscoelastic Simulation and Analysis on Deep Tectonic Deformation of the Longmen Shan Fault Zone

作　　者：高中[1] 华诚[1] 程晋[2] 陈棋福[3] 

机构地区：[1]复旦大学力学与工程科学系,上海200433 [2]复旦大学数学科学学院,上海200433 [3]中国地震局地震预测研究所,北京100036

出　　处：《复旦学报（自然科学版）》2012年第4期393-399,F0003,共8页Journal of Fudan University：Natural Science

摘　　要：根据龙门山断裂带地区的构造特征,建立该地区二维有限元模型.在考虑到深部构造发生粘弹性蠕动的条件下,利用粘弹性接触的有限元方法模拟计算上、下地壳和上地幔的滑动情况.模拟结果表明,龙门山断裂带及周围是应力集中区域,且随着时间的推移应力集中程度加剧.模拟还表明龙门山断裂带断层深处滑动速率比地表的滑动速率大,平均为3倍左右.因此,在龙门山断裂带地表滑动速率较小的情况下,速率较大的断层深部物质在滑动过程中则会产生能量高度的积聚,当能量积累超过极限强度,断层产生滑动,从而引发了地震.Based on regional tectonic characteristics of the Longmen Shan fault zone,a two-dimensional finite element model is established,and the contact viscoelastic finite element method is used to simulate slippage situation between the lower crust and upper mantle with considering the creep effects in the internal structure.The simulation results indicate that there are stress concentration areas in the Longmen Shan fault zone and the surrounded regions and the stress concentration strengthens with time.And the slip rate of the lower crust is larger than that in the upper crust,and generally,it reaches three times.Since smaller slip rate exists near the surface of the Longmen Shan fault zone,however,material of the lower crust,which has larger slip rate,can generate energy accumulation during sliding.Once the energy exceeds the ultimate strength,and the fault will slip,therefore an earthquake occurs.

关 键 词：龙门山断裂带 粘弹性断层 滑动速率 粘弹性有限元 

分 类 号：P315.5[天文地球—地震学]