常熟—太仓5.1级地震宏观烈度特征

THE INTENSITY CHARACTERISTICS OF THE CHANGSHU-TAICANG SHOCK OF 1990 WITH MAGNITUDE 5.1 (Ms)

1990年2月10日江苏常熟—太仓间发生5.1级地震,宏观震中位于太仓县沙溪乡,东径121°04′,北纬31°35′。震中烈度为Ⅵ度,其面积达23平方公里,高烈度值的点沿沙溪乡洞泾至胜利大队,呈北西西向分布,衰减慢,北东方向烈度衰减较快。烈度值分布具有不均匀性特征,出现烈度异常点和异常区,这次地震极震区等烈度线分布的方向和范围,与北西向新生代断陷盆地及控制盆地发育的边界断裂十分一致。

An earthquake with 5.1 (Ms) occurred between Changshu City and Taicang County,Jiangsu province on Fed.10,1990. The macroseismic epicenter of the quake was situated in shaxi district of Taicang County (30°35′N, 120°04′E). Thc epicentral in- tensity reached Ⅵ with area or 23 km^2. The axis of the area of intensity Ⅵ shows NWW direction. The intensity points show heterogeneous distribution. There are some unusual intensity points or areas. The direction of the isointensity distribution of the earthquake was consistent with the Cenozoic Era downfaulting basin and the boundary faults control- ling the basin to develop.