泛长三角地区主要活动断裂及地震活动基本特征

BASIC CHARACTERISTICS OF THE MAIN ACTIVE FAULTS AND SEISMIC ACTIVITIES IN PAN YANGTZE RIVER DELTA REGION

在系统收集整理前人成果资料基础上,结合基础地质和遥感解译,对泛长三角地区的主要活动断裂及其活动性进行了全面梳理和分析,并根据区域主要断裂的活动性与历史地震活动特征,进一步分析指出了该区需要特别关注的潜在震源区和地壳稳定性相对较差的区域。研究结果表明,该区主要发育38条活动性相对显著的活动断裂带,并以北东和北西走向两组活动断裂为主,前者以右旋走滑活动为主,后者以左旋走滑活动为主;其次为近东西走向,活动性较弱。进一步结合历史地震活动信息分析发现,其中的北东/北北东向断裂是区域上主要的控震构造和发震断层,其次是北西向断裂,这两组不同走向断裂带的交汇部位常常是地震发生部位,其中最显著的控震断裂是北东向的郯庐断裂与北西向的无锡—宿迁断裂。

On the basis of systematically collecting and sorting the data of predecessors ＇achievements, and combination of basic geology and remote sensing interpretation, we comprehensively analyzed and sorted out the main active faults and their activity in Pan-Yangtze River Delta region. According to the main regional faults and the activity of historical earthquakes,this paper further analyzed,and pointed out the potential focal region that needs special attention and region of relatively poor crustal stability in this area. The research results show that,there are38 active faults with relatively strong activity,mainly being in the directions of northeast and northwest. The former mainly on right lateral strike slip activity,the later mainly on left lateral strike slip activity. Then east-west faults with poor activity followed. Furthermore, combining the information of historical earthquake activity,we find that the convergence position of the two groups of fault zone with different directions are often the sites of earthquake occurrence. The most prominent controlled earthquake faults are northeast-orientational Tanlu fault and northwestorientational Wuxi-Suqian fault.