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.

本报告针对强震动加速度（strong motion acceleration）、强震动速度（strong motion velocity）与强震动位移（strong motion displacement）的峰值，给出了振幅衰减方程（amplitude attenuation equations）。该类方程的影响因子包括震级标度M、断层代表性距离Δ、断层长度、传播路径类型，以及穿过基底岩石（basement rocks）的震中距（epicentral distance）占比（0 < r < 1）。在观测台站附近，局地地质条件可通过场地参数（geologic site parameters）s（区分沉积物（sediments）与基底岩石）或沉积物厚度h进行表征。局地土体条件由场地土参数s_L描述，该参数可区分岩石、硬土与深厚土层工况。本研究考察了常用于描述强震动峰值振幅场地特异性的常见场地参数的相对重要性。研究发现，地表以下30米深度范围内（top 30 m below ground surface）的剪切波（shear waves）平均速度，并非影响加速度、速度与位移峰值振幅的显著参数。