Local site effects on weak and strong ground motion
Local site effects on weak and strong ground motion
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DOI：
10.1016/0040-1951(93)90262-i
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发表时间：
1993-02
期刊：
影响因子：
2.9
通讯作者：
K. Aki
中科院分区：
文献类型：
--
作者：
K. Aki
本文综述了局部地质对地震动影响的研究现状。在这方面的强震动研究是一个新的视野。沉积物地点的非线性放大似乎比地震学家过去认为的更为普遍。最近几个关于弱运动和强运动的观测表明，在沉积物场地的非线性放大可能是非常普遍的。首先，平均而言，在弱运动的情况下，对于12 Hz以下的所有频率，在较年轻的沉积物站点处的放大总是较大的;而在强运动的情况下，对于高于5 Hz的频率，这种关系是相反的。其次，从弱运动确定的放大因子的应用大大高估了在洛马普列塔地震期间观察到的震中距离约为50公里的沉积物网站的强运动。峰值加速度在均值曲线附近的方差随震级的增大而减小。最后，土工研究预计会出现上述非线性效应，无论是在偏离线性预测的幅度上，还是在非线性开始的阈值加速度水平上。
This is a review of the current state of the art in characterizing effects of local geology on ground motion. A new horizon is clear in this aspect of strong motion studies. Non-linear amplification at sediment sites appears to be more pervasive than seismologists used to think. Several recent observations about the weak motion and the strong motion suggest that the non-linear amplification at sediment sites may be very common. First, on average, the amplification is always greater at the younger sediment sites for all frequencies up to 12 Hz, in the case of weak motion; while the relation is reversed for frequencies higher than 5 Hz, in the case of strong motion. Secondly, the application of the amplification factor determined from weak motion overestimates significantly the strong motion at sediment sites observed during the Loma Prieta earthquake within the epicentral distance of about 50 km. Thirdly, the variance of peak ground acceleration around the mean curve decreases with the increasing earthquake magnitude. Finally, the above non-linear effects are expected from geotechnical studies both in the magnitude of departure from the linear prediction and in the threshold acceleration level beyond which the non-linearity begins.