Empirical equations describing attenuation of peaks of strong ground motion, in terms of magnitude, distance, path effects and site conditions, 1995

In this report we present amplitude attenuation equations for peaks of strong motion acceleration, velocity and displacement. These equations depend on magnitude scale, M, representative distance to the fault, ∆, fault length, type of propagation path and fraction of epicentral distance travelled through basement rocks (0 < r < 1). Near the recording station, the local geological conditions can be characterized either by the geologic site parameters s (distinguishing between sediments and basement rock) or by the depth of sediments, h. the local soil conditions are described by the local soil conditions are described by the local soil parameter s sub L (distinguishing rock, stiff and deep soil conditions). We examined the relative significance of the common site parameters, which are used to describe the site specific amplitudes of strong motion amplitudes. We found that the average velocity of the shear waves in the top 30 m below ground surface is not a significant parameter influencing the peak amplitudes of acceleration, velocity and displacement.

本报告针对强震加速度（strong motion acceleration）、强震速度（strong motion velocity）与强震位移（strong motion displacement）的峰值，提出了振幅衰减方程（amplitude attenuation equations）。这类方程的影响因素包括震级标度M、代表性断层距Δ、断层长度、传播路径类型，以及震中距中穿过基底岩石（basement rocks）的比例（0 < r < 1）。
在观测台站（recording station）附近，局部地质条件可通过场地参数s（区分沉积物（sediments）与基底岩石）或沉积层厚度h进行表征；局部土层条件由场地参数s_L（区分岩石、坚硬土层与深厚土层）描述。
本研究评估了当前用于表征场地特异性强震振幅的通用场地参数的相对重要性。
研究发现，地表以下30米范围内的剪切波（shear waves）平均速度，并非影响加速度、速度及位移峰值振幅的显著参数。