西北地区东部强震前地震活动演化特征

The evolutional features of seismic activity before strong earthquakes in eastern part of Northwest China region

通过对 1 90 0年以来西北地区东部 1 0次强震前不同时间尺度的地震分布特征以及演化过程的研究表明 ,西北地区东部强震前大多存在以下规律 :即在震中附近存在

In this paper, through study on earthquake distribution features and evolutional process of about 10 strong earthquakes occurred with different times scales in the eastern part of Northwest China region since 1900, we have found that there have existed the following law before strong earthquake in the region, i.e. there have existed long term anomalous features of earthquake deficiency larger than 5 magnitude near the epicenters and mid short term anomalous features of rising of moderate small earthquake activity level.