论文部分内容阅读
地震是地壳运动的一种表现方式.南海北部沿岸断块区的地震活动,通过对地面震中的分布、迁移,活动断裂的力学性质,地壳垂直形变,以及构造应力场等分析来进行发震条件的研究,早已引起广泛的注意,并取得了一些规律性的认识.在以预测地震危险区为目的的地质构造研究中,加强由浅部向深部,即由震中向震源,由地震带向地震层的对比研究,将有助于提高地震预报的水平.本区地壳结构有两个主要特征:其一是成层性,其二是块断性.两者互相结合组成了岩石圈的空间构造格局.南海北部沿岸地震活动显示为:在水平方向上沿块体两侧出现的块断错动(图1),以及在垂直方向上沿块体顶底不同层面出现的层间滑动.根据相关分析,对于M≥4的地震来说,后一种运动方式似乎起着主导的控制作用.
Earthquake is a manifestation of the crustal movement.The seismic activity in the fault block area along the northern coast of the South China Sea, through the analysis of the distribution and migration of earthquakes, the mechanical properties of active faults, the vertical crustal deformation and the tectonic stress field, Has long drawn extensive attention and gained some regularity cognition.In the study of geological structure for the purpose of predicting the seismic danger zone, the study from the shallow to the deep, that is, from the epicenter to the source, from the seismic zone to the seismic layer Will help to improve the level of earthquake prediction.The crustal structure in this area has two main features: one is stratification and the other is block-breaking, which combined with each other to form the spatial structure of the lithosphere Seismic activities along the northern coast of the South China Sea are shown in Figure 1, along the horizontal direction, along the two sides of the block, and along the vertical direction at different levels of the top and bottom of the block. According to the correlation analysis For the M≥4 earthquake, the latter mode of motion seems to play a dominant role.