论广州地区的地震构造及其发震危险性

广州的主要断裂构造是北北东向的广州—从化断裂带与近东西向的瘦狗岭断裂带与广州—三水断裂带。在北西西—南东东向区域构造应力场作用下,上述两条近东西向的断裂带组成右行左阶排列,导致岩桥区出现近东西向的附加挤压应力场,酿成广州—从化断裂带广州段内发生右行剪切运动,它是广州地区历史上数十次地震的发生带,是广州地区的主要发震构造;而右行左阶排列的近东西向断裂带的活动则是蕴育广州地震的原因。由于广州地区之主要发震构造规模不大,地震最大强度将以中强震为主,其极震区之地震烈度一般为六度,少数情况下可能接近七度。

SEISMOGENIC STRUCTURE IN GUANGZHOU AREA AND ITS SEISMIC RISK

Major fault structures in Guangzhou area are the NNE-trending Guangzhou -Conghua fault zone,sub-latitudinal Shougoling and Guangzhou - Sanshui fault zones. Under the effect of WNW - ESE - oriented regional stress field , the two sub-latitudinal fault zones have undergone dextral left -stepping dislocation, resulting in formation of sub - latitudinal additional compressive stress field, which caused dextral shear movement along the Guangzhou segment of Guangzhou -Conghua fault zone. Dozens of historical earthquakes occurred on this segment, which become a major earthquake-generating structure in Guangzhou area. The movement along the sub -latitudinal fault zones with dextral left -steppingning dislocation is a cause for preparation of earthquakes in Guangzhuou ares. The major earthquake generating structure is relatively small and the associated earthquakes are mainly of intermediate magnitude. The maximum intensities in their pleisto seismic areas are VI and less up to VII .