山地地形对地震动放大作用的机理探讨

从震后的调查和监测中发现,大地震会对山区地形形成的地质灾害,山地的局部位置,地震动加速度显著放大,甚至能使大型石块高速临空抛射,该文从地震波在介质中传播的角度,通过分析不同入射角度和不同反射界面地震波的反射叠加情况初步解释这一放大作用产生的机理,得出结论：（1）山地地形是产生地震动放大效应的主要原因;（2）放大效应与山体坡度密切相关（3）山脉走向会影响地震动水平分量的差异。并基于此对山区地形的震害防御工作提出建议。

Discussion on Mechanism of Mountainous Terrain Effect on Ground Motion Amplification

From investigations after earthquakes, it can be found that strong earthquakes generate serious geological disasters in mountainous ranges. Due to topography, the ground motion acceleration of some re- gions are greatly amplified, even some large stones are thrown into the air with high speed. In the light of seismic wave propogation, this paper analyzes the reflection stack of seismic waves from different treflec- tion angles and different reflecting interfaces, and gives a preliminary explanation for the mechanism of that amplification. The main conclusions are as follows： （1） The topography is the main reason leading to amplification effect of the ground motion; （2） Amplification effet is closely related to mountain slopes; （3） Mountain strikes cause differences in horizontal components. Based upon that, some suggestions are pro- posed for the earthquake disaster prevention in mountainous regions.