中国大陆及邻区地震活动格架及大地震空间分维特征

本文从板块碰撞观点出发,根据理论与实验的结果,强震震中分布,震源机制解,强震地表破裂带等资料,提出了中国大陆及邻区地震活动格架。它是两簇近似于对数螺线的构造滑移线,即在统一的区域应力场作用下,最大剪切应力和剪切应变集中的区、带。它们是控制和支配现今地震活动和构造运动的空间分布网络。这种网络结构,为我们研究地震活动空间分布规律,进行地震危险性分析,提出了一种新的途径和方法。据这些网络具有某种自相似性特点,进而研究了大地震(M≥7)的空间分维结构,计算了该区地震活动空间分布容量维随时间的变化,发现大地震发生前有降维的现象。

STRUCTURE OF SEISMICITY AND SEISMIC RISK IN MAINLAND OF CHINA AND ITS ADJACENT AREA,AND CHARACTERISTIC OF SPACE FRACE FRACTAL OF LARGE EARTHQUAKES

The seismicity structure in mainland of China and its adjacent area is proposed from the point of view of plate collidation on the basis of theory and experimental results. It is two clusters of structural slip lines similar to logarithm helical line, that is, it is the concentrated region and zone of maximal shear stress and strain which controll the space network of recent seismicity and tectonic movement under the action of unite regional stress field. This network structure provides a new way that space distribution law is studied and analysis of seismic risk is made. Based on certain characteristic of these network self-analogy, the space fractal structure of large earthquake (Ms≥7) has studied, and space distribution of seismicity and time variation of volume dimesion are calculaced in the region, and dedimesion phenomena prior to large earthquake is discovered.