体波地脉动单点谱比法研究

Spectral ratio of horizontal to vertical component research for body wave microtremors

采用弹性成层介质模型,应用概率分析方法,推导地下体波斜入射成层介质,在自由表面形成体波地脉动的水平分量与竖向分量谱比表达式。然后,通过大量模型计算,论证体波斜入射单层覆盖半空间形成地脉动水平分量与竖向分量谱比特性与场地传递函数间的关系。结果表明,利用地脉动单点谱比法分析体波为主要成分地脉动时,与场地水平向传递函数相比,可以得到较准确阻抗比大于3的场地卓越频率和偏小的场地放大因子。

The spectral ratio method抯 rationality of horizontal to vertical component (H/V method) for microtremors is discussed by an elastic layer over a half-space and probability model. The H/V expressions of body microtremors for layered media are derived. The feasibility of estimating the horizontal transfer function from H/V of microtremors is discussed. It is shown that the spectral ratio method of horizontal to vertical component can be used to estimate the site predominant frequency for body microtremors when the impedance ratio is more than 3. However the amplification factor of this method is smaller compared with site horizontal transfer function.