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经验反应谱地震动预测方程(GMPEs)的函数形式通常由地震动傅里叶谱模拟的概念导出,随后这些GMPEs由经验观测数据校准,所以,对特定地震场景的地震动预测不会构成重大问题。然而,当调整反应谱GMPEs来计算未被原始经验数据集覆盖的条件时,傅里叶谱模拟导出反应谱的假设可能会产生意想不到的结果。因此,几个问题出现了。例如,地震动傅里叶谱和反应谱的区别和相似之处是什么?如果它们是不同的,什么机制可以解释这样的差异?对傅里叶振幅谱(FAS)所做的调整在反应谱中怎么表示?本文利用随机振动理论(RVT)探讨了地震动傅里叶谱和反应谱之间的关系。借助简单的Brune震源模型~([1-2]),在固定震级和距离的情况下,用RVT生成了加速度谱。RVT分析表明,反应谱低频谱值标定可以视为与相应傅里叶谱标度值等同。然而,反应谱高频谱值受到了带宽很大的傅里叶谱的控制。实际上,地震动峰值加速度不能反映高频地震动特征,它受到了整个地震动傅里叶谱的控制。此外,本文说明了对FAS做的调整如何相似或区别于对反应谱坐标所做的相同的调整。为此,我们研究了调整应力参数(Δσ)(震源项)和调整反应场地响应的属性(V_S-κ_0)这两种情况。
The functional form of the empirical response spectrum ground motion prediction equations (GMPEs) is often derived from the concept of ground motion Fourier spectrum simulations, and these GMPEs are subsequently calibrated by empirical observations so that the prediction of ground motion for a particular seismic scenario does not pose a significant problem . However, when the response spectra GMPEs are adjusted to calculate the conditions that are not covered by the original empirical dataset, the assumption that the Fourier spectrum is simulated to derive the response spectra may yield unexpected results. Therefore, several problems have arisen. For example, what are the differences and similarities between the ground motion Fourier spectrum and the response spectrum? If they are different, what mechanisms can account for such differences? The adjustments made to the Fourier amplitude spectrum (FAS) How to express it? In this paper, the relationship between the ground motion Fourier spectrum and the response spectrum is discussed by using the random vibration theory (RVT). With the simple Brune source model ~ ([1-2]), an acceleration spectrum was generated with RVT at a fixed magnitude and distance. The RVT analysis showed that the calibration of the low spectral values of the response spectrum can be regarded as equivalent to the corresponding Fourier spectrum scale value. However, the high spectrum of the response spectrum is governed by a large bandwidth Fourier spectrum. In fact, the peak acceleration of ground motion can not reflect the characteristics of high frequency ground motion, which is controlled by the whole ground motion Fourier spectrum. In addition, this article shows how adjustments made to FAS are similar or different from the same adjustments made to response spectrum coordinates. For this reason, we studied two cases, adjusting the stress parameter (Δσ) (source term) and adjusting the response field property (V_S-κ_0).