【摘要】 基于美国西部80条基岩上的近场强震记录,采用Nakayama方法生成记录的渐进谱,并参照Kameda方式,用统计方法建立了根据震级、距离等地震参数预测渐进谱的统计模型.提出一种以渐进谱为目标谱的生成幅值和频率非平稳地震加速度时程的迭代方法.由于考虑了渐进谱幅值和相位的相互影响,所生成的时程的相位也是时频非平稳的,并在相位调整中识别了相位谱增量符号以加速迭代收敛进程.最后根据统计回归的目标渐进谱模型和本文提出的拟合目标渐进谱的方法,可生成不同震级、距离条件下的幅值和频率均非平稳的地震加速度时程.更多还原

【Abstract】 By using the technique for evolutionary power spectrum proposed by Nakayama and with reference to the Kameda formula, an evolutionary spectrum prediction model for given earthquake magnitude and distance is established based on the 80 near-source acceleration records at rock surface with large magnitude from the ground motion database of western U S. Then a new iteration method is developed for generation of random accelerograms non-stationary both in amplitude and frequency which are compatible with target evolutionary spectrum. The phase spectra of those simulated accelerograms are also non-stationary in time and frequency domains since the interaction between amplitude and phase angle has been considered during the generation. Furthermore, the sign of the phase spectrum increment is identified to accelerate the iteration. With the proposed statistical model for predicting evolutionary power spectra and the new method for generating compatible time history, the artificial random earthquake accelerograms non-stationary both in amplitude and frequency for certain magnitude and distance can be provided.更多还原