九江—瑞昌地区重磁数据处理解释与地震灾害评价

Gravity and Magnetic Data Processing and Earthquake Disaster Assessment of Jiujiang ——Ruichang Area

九江-瑞昌地区地处扬子地台北缘,历来地震灾害较少,但2005年11月的九江-瑞昌5.7级地震引起了人们对该区地震灾害的关注。本文对航磁数据进行延拓、方向导数和小波多尺度分解等各种处理,获得了该区的断裂体系分布,同时还提取了与居里面有关的区域场并反演了居里等温面,得出了该区居里面深度图。结果表明,九江-瑞昌地区处于华北板块与扬子板块陆陆碰撞的接触部位,是襄樊-广济断裂、郯庐断裂和江南断裂的交接部位,同时也处于居里面南北过渡的梯度带上,是地质构造上容易发生地震的地段,九江-瑞昌5.7级地震并非偶然,应当予以重视。这些工作为该区的地震防灾工作提供了必要的基础资料。

Jiujiang and adjacent areas are located in the north of Yangtze platform and earthquake seldom takes place there. However, in November 2005, the Jiujiang - Ruichang Ms 5.7 earthquake aroused people＇s concern. In this paper, we use continuation, directional derivative and wavelet multi-scale analysis of aeromagnetic data to study the fault system distribution. Then we use field separation and Curie isothermic surface inversion in frequency domain to obtain the Curie surface map in depth. The results show that Jiujiang and adjacent regions are located in the zone of continental-continental collision between North China Plate and Yangtze plate, and they are in the intersection of Xiangfan-Guangji fault, Tanlu fault and Jiangnan fault, which also lie in the gradient zone of Curie surface where earthquakes will happen easily from the perspective of geological structure. So this study provides the necessary information for the prevention of earthquake disasters.