九寨沟M_s4.1级余震薛家坝场地地震动响应监测数据分析

Analysis of Ground Motion Response Monitoring Data of Xuejiaba Site of M_s4.1 Aftershock in Jiuzhaigou

九寨沟“8.8”地震后余震一直持续,对灾区人民生命财产安全造成了极大地威胁,进行余震监测研究意义重大。通过对薛家坝不同地基类型、不同高程处各监测点的地震动响应分析揭示:处于深厚覆盖层场地的1#监测点记录到的峰值加速度>2#监测点>参考点,说明局部范围内不同地基类型对地震波的放大效应要比地形放大效应更为显著;1#监测点阿里亚斯强度最大值分别为2#及参考点的1.5、5.1倍,而处于相同地基条件的2#监测点阿里亚斯强度最大值约为参考点最大值的3.5倍;傅氏谱分析发现:深厚覆盖层场地对地震波的放大作用强于完整基岩场地,2#监测点同一高程不同埋深对地震波具有选择放大作用,距离洞口越近放大作用越明显。

After the “8.8” earthquake in Jiuzhaigou,the aftershocks have continued,posing a great threat to the safety of people's lives and property in the disaster areas.It is of great significance to carry out aftershock monitoring research.Through the analysis of the ground motion response of different types of foundations and different elevations of Xuejiaba,it is revealed that the peak acceleration>2# monitoring point>reference point recorded in the 1# monitoring point of the deep overburden site indicates the local range.The amplification effect of different ground types on seismic waves is more significant than the terrain amplification effect;The maximum value of Arias intensity of 1# monitoring point is 2# and 1.5 times and 5.1 times of reference point respectively,while 2# monitoring in the same foundation condition The maximum Arias intensity is about 3.5 times of the maximum value of the reference point;Fourier's spectrum analysis shows that the deep-coverage site has a stronger amplification effect on seismic waves than the complete bedrock site,and the 2# monitoring point has the same elevation and different depths to seismic waves.With selective amplification,the closer to the hole,the more obvious the amplification effect.