中国东北地区地震空间分布与主要断裂带、深部构造及应力场关系

中国东北地区在北东东向应力场控制下, 地震有其特殊性。地震空间分布和深度统计结果表明, 东北地区地震主要受岩石圈断裂(开原-赤峰断裂带) 控制, 以44°N为界, 南北具有明显差异。北部地震发生的数量少于南部, 震源深度主要集中在4～6 km和8～12 km两个深度范围内; 而南部主要集中在8～12 km和28～30 km两个深度范围内。发震深度分析显示, 开原-赤峰、郯庐断裂带、大兴安岭断裂带下可能存在地温较低的区域, 使地震可以在深部孕育。地震分布的Vp和Vs剖面资料的研究暗示, 断裂与速度变化带、断裂与断裂的相交区域是地震易发生区域。

Earthquake space distribution and its relationships with main faults, deep structure and stress field in Northeast China

Under the control of northeast-east stress field, the earthquakes in Northeast China have their special characteristics. The statistical results of earthquake space distribution and depth indicate that the earthquakes are mainly controlled by the lithospheric fault (Kaiyuan-Chifeng fault) in Northeast China with great differences between the north and the south. The earthquakes occurred in the north are less than in the south, divided by the boundry of 44°N, and the earthquakes mainly concentrated in 4～6 km and 8～12 km in depth in the north, and in 8～12 km and 28～30 km in the south. The analysis of earthquake depth indicates that there have probably low thermal areas beneath Kaiyuan-Chifeng fault,Tanlu fault and Daxinganling fault, which provide the conditions for earthquakes getting ready in deep part. The analysis of Vp and Vs sectional data of earthquake distribution suggests that the earthquakes are often centralized in the intersectant zones of faults with velocity change zone and faults with faults.