汶川8.0级地震地震动峰值加速度衰减特性分析

Peak Ground Acceleration Attenuation Relationship of Wenchuan 8.0 Earthquake

利用汶川8.0级特大地震中107个台站所获取的强震动加速度记录进行回归统计分析,给出了此次地震的地震动峰值加速度衰减关系.将107个台站分为上盘区和下盘区两部分,其中77个台站属于上盘区,30个台站属于下盘区.对上/下盘区进行了详细的地震动衰减特性对比分析,主要包括两个区的水平向和竖向峰值加速度衰减关系、竖向与水平向峰值加速度比值变化以及是否存在上/下盘效应等,揭示了汶川地震近断层地震动一些特性.

The strong motion recordings at 107 observation stations from Wenchuan 8.0 earthquake in 2008 are analyzed with the statistics method.For comparising the ground motions in two different regions—the hanging wall and footwall regions,the 107 observation stations are divided into the two regions.There are 77 stations in the hanging wall region and others in the footwall region.The acceleration attenuation relationships of strong motions were analyzed by the least squares method.Two horizontal and Two vertical acceleration attenuation relationships are obtained.Based on these relationships,the characteristics of strong motions,including the horizontal and vertical acceleration attenuations,the variation of ratio of peak accelerations in horizontal and vertical motions,and the hanging wall and footwall effects are discussed to find out the difference of strong motions in the two regions.Finally,attenuation models are compared with some well-known attenuation relationships.