南北地震带中南段断层现今活动

The recent fault activity along the middle and southern segments of South-North Seismic Belt

分析了南北地震带中南段流动形变资料 ,研究了断层现今活动的空间分布及特征。结果表明 ,红河断裂带、楚雄 -通海断裂带及鲜水河断裂带活动水平最高 ,龙门山断裂带活动最弱 ;断层活动水平近年总体未见加剧或减缓。研究认为 :强震前区域断层活动加剧 ;断层突然错动引起的位移在地质资料显示的断层位移中占主要成分 ;近期南北地震带南段仍将保持近 2 0年强震频发的态势 ,中段近年有发生 6级地震的可能 ;楚雄 -通海断裂带中段及鲜水河断裂带两端 。

In this paper the authors have analyzed the data of mobile geodetic deformation along the middle and southern segments of South North Seismic Belt and studied the spatial distribution and characteristics of fault activity in recent time. The results show that the fault activity rate along Honghe Chuxiong Tonghai fault and Xianshuihe fault is the highest and Longmenshan fault is the slowest. Fault activity levels in the recent years have not intensified or become weaker in general. Through studies the authors put forward several viewpoints as follows: Regional fault activity strengthens before strong earthquakes. Sudden fault displacement possesses an important part of fault movement, which exhibited in the geologic data. Along southern segment of South North Seismic Belt in the near future there will keep the same state of high frequency of strong earthquake occurrence as in the past 20 years. Along the middle segment of South North Seismic Belt there is a possibility that the earthquake with M S=6 may occur in recent years. The middle of Chuxiong Tonghai fault and the two ends of Xianshuihe fault are risk locations of strong earthquakes, which deserve the notice.