序列型地震动物理随机模型研究

通过引入主震与余震间的震级、震源参数以及峰值速度的物理关系，将已有的单震物理随机模型推广到序列型地震动，并利用实测主余震记录拟合获得了模型中各参数的概率分布，进一步结合窄带谐波叠加法实现了序列型地震动的工程模拟。从典型样本时程和反应谱两个层面上与实测地震动记录进行了对比，结果表明模拟地震动具有与实测记录相同的频谱特性，能够反映实际地震动的时域、频域非平稳性，建议模型所给出的反应谱均值和标准差与实测记录的统计结果基本一致，可用于序列型地震作用下工程结构的抗震性能分析。

STUDY ON PHYSICAL RANDOM MODEL OF SEISMIC SEQUENCES

This study extends the existing physical random model for a single earthquake to sequence earthquakes as main shock-aftershock by introducing physical relationships of key parameters such as the magnitude, hypocenter and peak velocity between main shock and after shock. Field recorded earthquake records were adopted to determine the coefficients of the probability density function of all these parameters. Then, the superposition method of narrow band harmonic wave groups was utilized to simulate sequence earthquakes, which were compared with real records in terms of time-domain characteristics and response spectrum. The results show that the synthesized ground motions from the proposed model has the close mean value and standard deviation in the response spectrum and non-stationary features in time-and frequency-domains with that of the real records. The proposed model can be used for aseismic performance analysis of civil structures under sequence earthquakes.