摘要
震级和地震波传播途径均有测量误差和不确定性。本文考虑震级和距离的不确定性,用作者提出的回归多随机变量间相关关系的一致加权最小二乘法,对地震动水平峰值加速度(PGA)、速度(PGV)和位移(PGD)的衰减关系进行了研究,在衰减模型中考虑了地震动的近场距离饱和与震级饱和特性。研究结果表明,考虑震级和距离的随机性后,地震动的距离与震级标定系数比常规方法增大16—28％,大震的地震动估计值及小震近场的地震动估计值均高于用常规方法得到的结果;高频地震动具有明显的近场距离与震级饱和特性,且距离饱和范围随震级的增大而加宽;场地条件对地震动衰减规律有明显影响,同时这一影响又同距离和震级密切相关。本文预测结果与新近发生的三大地震(M_s=8.1,7.8,7.1)的观测资料很吻合。
Accounting for the measuring errors or uncertainties of magnitude and distance in addition to ground motion, the attenuation laws for peak horizontal ground acceleration (PGA), velocity(PGV),and displacement(PGD)are studied with a weighted consistent least square regressional method proposed by the authors to obtain the functional relation among several random variables. The saturation of ground motions near epicenter with respect to both magnitude and distance is also emphasized in the models. The result is that the scaling factors for distance and the linear term of magnitude in the attenuation relations regressed by the suggested method are about 16 - 28% in average larger than those from the routine method. The ground motion estimates are somewhat higher than the routine values for large earthquakes or at near field for small events. The peak values saturate near the source and the scope of saturation widens with the increase of magnitude. The site geological conditions affect the ground motion attenuation very much and this effect is related with distance and magnitude at the same time. The prediction from the new model is very well consistent with the observed data from the three large earthquakes recently occurred and not considered in the re gression.
出处
《地震工程与工程振动》
CSCD
北大核心
1992年第2期1-11,共11页
Earthquake Engineering and Engineering Dynamics
基金
地震科学联合基金
