北部湾海域地震构造背景研究

本文从构造背景、断裂构造、地球物理场、地震活动性和震源机制等方面,分析了北部湾双震的发震构造条件,认为北东东向的乌石凹陷边界断裂为主要发震构造,而北西向断裂仅起到应力集中和调节作用。同时本文还认为,北部湾盆地内的地震活动主要与晚新生代沉降中心相关,且次级凹陷——北东-北东东向边界断裂是重要的发震构造,而其较大弧度的转折部位或与北西向断裂交汇部位是重要的发震部位。

Research on Seismotectonic Background of Beibu Gulf Shallow Sea Area

Based on the study of geologic structure, faults, geophysical fields, seismicity and earthquake focal mechanism, the seismogenic structures of two earthquakes occurred in Beibu gulf shallow sea area are discussed in this paper. Our results show that the NEE trending faults along the boundary of Wushi depression are the dominating seismogenic structure, and the NW trending faults are the key factor of stress concentration. The results also indicate that the seismicity in the study area has a significant relationship with the deposition center of the late Cenozoic in Beibu gulf, and their NE-NEE trending boundary faults are important to identify seismogenic structure. Finally, the special arcuate segment of the fault or the intersection site with the NW trending faults and the NE-NEE trending boundary faults is the potential location for the occurrence of earthquakes in future.