SV波入射下河谷地形地震动分布特征分析

基于显式有限元方法和人工透射边界，对二维河谷地形在3条地震动波以SV波形式垂直入射和30°斜入射下进行了地震反应分析，比较了河谷地表各观测点地震动的差别，探讨了河谷地形地震动空间分布特征。结果表明，河谷地形对地震动分布具有重要影响，沿河谷斜坡顶到谷底的各观测点地震动峰值加速度（PGA）存在显著差异，地震动位移存在差动现象，地震动加速度反应谱在大于1 Hz的高频段差别明显。入射角度是影响场地地震反应的重要因素，斜入射时各观测点PGA和相对位移的离散程度明显大于垂直入射情形。

Characteristic analysis of ground motions of canyon topography under incident SV seismic waves

Using explicit finite element method and artificial transmitting boundary,the seismic response analysis of a 2D canyon model is performed under three incident SV seismic waves respectively with the assumptions of vertical incidence and oblique incidence at the angle of 30 degrees.The canyon surface ground motions have been compared and the distribution characteristics of ground motions are summarized.It indicates that canyon topography has significant influence on the distribution of ground motions.The peak ground accelerations(PGA) vary greatly from the bottom of the slope to the upper corners.Ground acceleration at high frequency band beyond 1 Hz has been more greatly amplified.And the canyon ground surface has been characterized by relative displacements(RD).It is also found that the incidence angle shows significant influences on the ground motions.Under oblique incident SV waves,the discrete degree of the PGA and RD observed at the canyon surface are much larger than that under vertical incident SV waves.