北部湾地震的震源机制及地震地质条件

FOCAL MECHANISM AND SEISMIC GEOLOGIC CONDITIONS OF THE BEIBUWAN EARTHQUAKES

对北部湾地震的震源机制解和地震地质条件进行了详细分析，认为靖西－崇左断裂带过震中的北北西向断层为发震断裂；四会－吴川断裂带过震中的北东东向断层为控震构造。震源构造应力场的主压应力方向为北西－南东向，发震断层的活动方式既有垂直差异运动又有走滑运动。

The focal mechanism solution and seismic geologic conditions of the Beibuwan earthquakes are discussed.The fault which belongs to Jingxi-Chongzuo fault zone in NW-SE direction and crosses the epicenter is the seismogenic fault.The fault which belongs to Sihui-Wuchuan fault zone in NE-SW direction and crosses the epicenter must have some effects on this seismic sequence.The main pressure direction of the focal stress field is in NW-SE direction.The Beibuwan basin and the fault in and around it inherit the past active model still now.