渤海海峡跨海通道工程区断裂活动性及地震分布特征

利用近年来采集的高分辨率地震剖面资料，编制了渤海海峡跨海通道工程区主要活动断裂分布图，并对其中各断裂的垂直活动速率进行计算，发现渤海海峡跨海通道工程区内NE—NNE向断裂晚更新世以来的平均垂直活动速率为0103 mm/a，NW向断裂的平均垂直活动速率为0080 mm/a，其中NE—NNE向断裂和NW向断裂的活动速率呈由南到北逐渐增强的趋势，NW向断裂还表现出明显的自西向东活动速率逐渐增强的特点。另外，通过与现代小震资料和历史地震资料进行对比，发现研究区内地震分布具有不均匀性，地震活动性随着与断裂之间距离的增加而减弱，且在断裂交点和端点处活动性较强。研究区内地震的这些分布特征能够用弹性回跳学说解释。此外，研究区内地震活动性与断裂的水平位移速率关系可能更为密切，其与断裂垂直活动速率的关系还需要进一步研究。

Fault Activity and Characteristics of Earthquake Distribution in the Engineering Area of Bohai Strait Cross sea Channel

Newly collected data of high resolution seismic sections have been used in the analysis of distribution characteristics and the vertical activity rate of active faults in the engineering area of Bohai Strait Cross sea Channel. This analysis shows that the average vertical activity rate of NE NNE trending faults is 0103 mm/a, and that of NW trending faults is 0080 mm/a since the Late Pleistocene. The analysis results also show that the vertical activity rate is gradually increasing from south to north in both NE NNE trending faults and NW trending faults, and the NW trending faults show a significantly trending of gradually increasing from west to east. By comparing with the modern small earthquakes and the historical seismic data, it is found that the earthquake distribution in the study area is inhomogeneous, and the seismicity is weakened with the increase of the distance from the fault, and the activity is strong at the intersection point and the end point of the fault. The elastic rebound theory can be used to explain the distribution characteristics of earthquakes. Additionally, the relationship between the seismic activity and the horizontal displacement velocity of the fault is likely to be closer, and the relationship between the seismic activity and the vertical velocity of the fault needs further studies.