沈阳市F6断层的强地面运动分布模拟

Strong Grand Motion Distributing Simulation on the F6 Fault in Shenyang City

目的研究沈阳市F6断层在设定地震6.0级时的强地面运动分布,为避免城市活动断层的地震破坏和为重要建筑合理的抗震设防提供依据.方法通过断裂所处应力环境、形变特征及活动性、结构、规模、地震活动、深部构造等综合分析,确定F6断层的地震危险性.以深、浅层人工地震、钻探、多道直流电法、探地雷达和地脉动数据为基础,建立了沈阳市接近真实的三维地下速度结构模型,强地面运动计算采用了三维有限差分法和统计学格林函数法的合成方法.结果 F6断层为中更新世活动断裂,最大潜在地震震级为6.0级;F6断层的震源模型为具有两个Asperity(凹凸体)的矩形断层:一个最大18km2的Asperity和一个7km2的Asperity.在设定地震作用下,F6断层强地震动PGA的影响范围集中于F6断层两侧,最大值达到285gal;PGV、PGD的分布形态与PGA相似.结论 F6断层发生6.0级时在沈阳市能够形成带状的强地面运动分布,其幅值甚至超出大震设防水准.

In order to avoid earthquake damage related to active fault, and to provide anti-seismic basis for important buildings＇ fortification. This paper analyzes the strong grand motion distribution in Shenyang city based on the F6 fault of given Ms 6. 0 earthquake, By analyzing F6＇s stress condition, deformation, activity, structure, scale, seismic activity, deep structure etc. the seismic hazard of F6 can be determined. Based on deep seismic reflection sounding, shallow seismic reflection sounding, trills, multichannel direct current sounding, geological radar data , the 3-D underground wave speed structure model is established and optimized. The synthetic means of 3-D limited differential and statistical Green＇ function are applied in thestrong grand motion calculations. The F6 fault is mid-pleistocene active and its potential magnitude is 6. 0. As to the F6 rectangular fault,it has 2 Asperities,one is about 18 km^2 and the other is about 7 km^2. Under Ms 6. 0 earthquake on F6, the influencing area of PGA is around F6 fault, its maximum value can get to 285 gal,PGV,PGD are similar to PGA. When Ms 6. 0 earthquake on F6 happens,it could appear a belted strong grand motion distribution in Shenyang city, its value even exceed the fortification level of large shock.