【摘要】 中国大陆位于欧亚板块的东南部,受到印度板块、太平洋板块和菲律宾海板块的碰撞挤压与俯冲作用,其构造应力场形态和动力学机制相当复杂.本文采用伪三维有限元方法,以世界应力图2008年版本数据(WSM2008)的应力方向和应力型两类指标作为主要约束,对中国大陆及邻区的动力驱动机制进行数值模拟,给出了中国大陆周边地区板块边界力的大小和方向估计.同时对3个典型情况的数值模型进行了分析.结果显示,软流层静压推力对该区域构造应力场影响相对较小,板块边界力作用则起主导作用;印度板块在喜马拉雅造山带对欧亚板块的碰撞控制了中国大陆地区应力场的基本形态,是形成川滇地区走滑型地震为主的重要原因;琉球海沟—南海海槽俯冲带边界力显示了挤压-张性的分段特性,贝加尔裂谷表现为拉张作用.进一步的分析表明,中国大陆大部分区域内最大水平剪应力分布图像与该地区地震辐射能量密度的分布存在较好的空间正相关性.更多还原

【Abstract】 Located in the southeast of Eurasian plate,China mainland is subject to collision,extrusion and subduction of Indian plate,Pacific plate and Philippine Sea plate,so the tectonic stress field there and its dynamical mechanism are very complex.Using a pseudo 3D finite element method and with the orientation and regime indicators from World Stress Map 2008(WSM2008) database as principal constraints,this paper numerically simulated driving forces on China mainland and adjacent areas,and estimated the magnitude and direction of plate boundary forces.We analyzed three typical models.The results show that the asthenospheric static push forces have small influence on the tectonic stress field,while the plate boundary forces play a significant role.The collision of Indian plate with Eurasian plate in the Himalayan orogenic belt controls the basic pattern of stress field in China mainland,and is an important cause of lots of strike-slip earthquakes in Sichuan--Yunnan region.The boundary forces of Ryukyu Trench--Nankai Trough subduction zone display push-to-pull segmental feature.Baikal rift is under the action of pull force.Further analysis reveals that in most areas of China mainland the distribution of maximum horizontal shear stress shows a good positive spatial correlation with the radiated seismic energy density in this region.更多还原