我所2016年发表论文欣赏-第二十五期

地球所研究生会 · 公众号 · · 2017-06-26 14:59

正文

题目

以形变观测为约束的芦山Ms ７．０地震孕震机理数值模拟研究

作者

祝爱玉１，张东宁１，２，郭颖星１

发表刊物

《地球物理学报》

摘要

本文以２０１３年４月２０日芦山 Ms ７．０地震前后在震中附近开展的形变观测研究结果为约束，利用震区天然地震成像、大地电磁测深、人工地震探测剖面、余震精确定位、震源破裂过程、地质考察、ＧＰＳ观测、构造应力场等结果，建立了芦山地震震中及邻近地区的深浅部构造二维有限元数值模型，探讨了青藏高原向东挤出运动、区域地形特征、地壳内低速带和滑脱面、震区主要断裂带活动等可能因素对芦山地震孕育和破裂的控制作用．模拟结果显示，汶川地震后的青藏高原东部物质相对四川盆地运动速率增大是引发或加快芦山地震发生的主要动力学控制因素，龙门山断裂带西侧上中地壳内部低速带和滑脱面的存在是控制芦山地震震源位置的重要条件，其他因素则是控制龙门山断裂带长时间尺度区域构造活动的动力学因素；同时本文给出了主震破裂为复杂 “ ｙ ”型双破裂面的同震位移，模拟计算的地表垂直位移与观测结果一致，进一步支持了余震精确定位提出的主震为 “ ｙ ”型破裂面的推测．关键词芦山地震； “ ｙ ”型破裂；发震构造；动力学控制因素；有限元数值模拟

题目

Numerical simulation of the segmentation of the stress state of the Anninghe-Zemuhe-Xiaojiang faults

作者

ZHU AiYu, ZHANG DongNing * & JIANG ChangSheng

发表刊物

《SCIENCE CHINA Earth Sciences》

摘要

We established a three-dimensional finite element model of the Anninghe-Zemuhe-Xiaojiang faults region using contact surfaces of different sizes to describe the spatial segmentation characteristics of the faults. Our model is based on constraints from GPS observations, models of the crust and upper mantle, precise earthquake locations, the tectonic stress field, the slip rate of the faults, and the rheology of the lithosphere in the Sichuan-Yunnan area. Considering the influence of strong earthquakes since A.D. 1327, we analyzed the main controlling factors of the characteristics of the strong earthquakes and also studied by numerical simulation the possible areas of future earthquake risk and their relationship with tectonic stress. The numerical results showed that the gravitational potential energy of the Qinghai-Tibet Plateau and the interaction of adjacent blocks are the main kinetic factors affecting the characteristics of the tectonic stress distribution. There appears to be some correspondence between the distribution of tectonic stress and the b value; however, we also found that some low b value locations correspond to regions of lower stress. This contradiction may be the result of some comprehensive factors, such as the release of strain energy caused by strong earthquakes.