通过对1918年南澳大地震(M=7．5)震中区的地震地质考察和记录史料比较研究分析,该地震震中位于北东东向滨海断裂带与北西向黄岗水断裂带的交汇处,地震所产生的北东东向逆冲断层和北西向张性断裂反映了地震的震源应力场为北西-南东向挤压,北东-南西向拉张;烈度X度极震区为一呈北东东向和北西向延伸的“X”型面状分布,发震构造属北东东向与北西向相交切的断裂构造型式,以北东东向的滨海断裂带为主,北西向的黄岗水断裂为辅．根据穿越震中区的海陆联合深地震探测的最新研究成果,滨海断裂带为一个上下连续倾向南东的低速破碎带,断裂带西北侧为正常型陆壳,厚30 km;断裂带东南侧为减薄型陆壳,厚25-28 km．滨海断裂带为华南亚板块与南海亚板块的分界断裂,是南海东北部的重要控震构造和发震构造．滨海断裂带与上地壳下部的低速层的交接构造部位形成南海东北部的重要应力集中带和应变能积聚带,是地震孕育、发生的深部动力学条件． Through the seismic geological survey and historical data comparison of the epicenter area of ​​the 1918 Nan’ao Earthquake (M = 7.5), the epicenter of the epicenter is located at the junction of the north east-east coast fault zone and the northwest-west Huanggangshui fault zone. Earthquakes The resulting NE-trending thrust faults and NW-trending tensional faults indicate that the source stress field of the earthquake is NW-SW squeeze and NE- The “X” shape distribution extends in the east, north and west direction. The seismogenic structure belongs to the fault structure type with the NE-NE and the NE-NE intersecting. The northeast-east coast fault zone is mainly composed of northwestward Huanggang Water fracture as a supplement. According to the latest research results of sea-land combined deep seismic exploration across the epicenter area, the Binhai fault zone is a low-speed fractured zone with a continuous up-and-down tendency toward the south east. The northwestern fault zone is a normal continental crust with a thickness of 30 km. The southeast of the fault zone is reduced Thin continental crust, 25-28 km thick. The Binhai fault zone is the boundary fault between the South China subplate and the South China Sea subplate. It is an important seismic control structure and seismogenic structure in the northeastern South China Sea. The junction between the Binhai fault zone and the low velocity layer in the lower part of the upper crust forms the important stress concentration zone and strain energy accumulation zone in the northeastern South China Sea. It is a deep dynamic condition that occurs during the earthquake.