新疆5级以上地震前后弱震条带的变化特征

CHARACTERISTICS OF THE SEISMIC BAND BEFORE AND AFTER THE EARTHQUAKES WITH MAGNITUDE≥5.0 IN XINJIANG REGION

本文对新疆1971—1983年北天山及南天山东段发生的12次Ms≥5.0级地震进行了清理,震前出现弱震条带的有7次,其中变化显著的有3次;2次因其它地震干扰不易分析;2次地震条带不明显。震前弱震条带有以下特征:在新疆较高活动水平下,地震条带往往是原地震带上地震活动强弱的一种变化。某些地震前出现背景性或双条带,一次地震的前震可能是组成条带的重要部分:同一区域的弱震条带具有继承性;地震条带往往是Ms≥6级地震前空区的某些边段。用弱震条带预报地震是困难的,文中对地震条带的具体判据,分析方法以及其它有关问题进行了讨论。

This paper studied the seismicity before and after the twelve earthquakes with magnitude≥5.0 in the North Tianshan Mountain and the Eastern part of the South Tianshan Mountain in Xinjiang region from 1971-1983.The results shown that there are seven weak seismic bands before some of these earthquakes,of which,three seismic bands are appa.rent,and two can’t be analysed because of the effects of other earthquakes,the other two are not before earthquakes.lt is still difficulty to predict great earthquakes with weak seismic bands.The concrete estimations,the analytic methods and some concerned problems of the seismic bands are discussed in the paper.