地震发震大尺度结构

Large Scale Tectonics Related with Earthquake

一次大地震发生前,地震活动在其未来震中区近处,常会表现平静。但着眼于全球大尺度规模,则可观测到颇具特色的地震活动性图像。较为普遍出现的图像是直线型与圆弧型,以及构成这些图像的主要地震事件的等间距性。本文认为大地震发震结构可以具有全球规模的大尺度,这些地震发震大尺度结构主控着大地震发震的短临进程,对认识地震成因机制具有重要意义。同时文中还给出中国近年发生的数次大震(1976唐山M7.8;2001昆仑山口西M8.1;2008汶川M8.0)前呈现的地震发震大尺度结构,很明显它们具有一定的预测意义。

Before a large earthquake,its central region usually shows some quiescence.However,as viewed from a global large scale,the seismic activity pattern does show quite distinct characteristics.Linear pattern and circular arc pattern appear more common;the events constructed from above patterns are distributed on an equal span of distance as well.It has been recognized that the tectonics associated with the earthquake generation present a large scale nature globally.These large scale tectonics related with the earthquake generation control the progress of the earthquake preparation in a short term,and are very important in understanding the mechanism of earthquakes.This paper reviews the cases that large scale tectonics related with earthquake generation show before several large earthquakes（Tongshan earthquake of M7.8,1976;Kunlun Mountain earthquake of M8.1,2001;Wenchuan earthquake of M8.0,2008） occurred in recent years in China.That gives some food for thought on earthquake predictions.