宁夏及邻近地区震源机制解特征

FEATURES OF FOCAL-MECHANISM SOLUTIONS IN NINGXIA AND ITS NEIGHBORING REGION

摘要:

采用在吴尔夫网上作图的方法求得了宁夏及邻近地区372个地震震源机制解,再以各次地震的主压、主张应力轴资料在吴尔夫网上求出了该地区主压应力方向和主张应力方向.其P轴的优势方向在北东30°~70°之间;T轴的优势方向在北西300°~330°之间.由该地区主压和主张应力以近水平方向为主,认为发生地震的断层运动形式是以走滑运动为特征.

Abstract:

The focal-mechanism solutions of 372 earthquakes in Ningxia and its neighboring regions are evaluated by using Nulff net. Basing on these data the direction of principal compressive stress and principal strain stress in this region are obtained by use Wulff net again. The dominant direction of P axle is NE 30°~70°,and one of T axle is NW 300°~330°. According main acting force is horizontal or nearly horizontal,most of the tectonic faults which causing earthquake should be strike-slip or nearly strike-slip faults.