基于实测数据和等效脉冲模型的近断层地震动复原方法

Near-fault ground motion reconstruction method based on observed data and equivalent pulse model

摘要:

近断层地震动是判断震害程度的重要依据,但一次地震中获取的近断层地震动记录数量往往较少。为解决近断层区域工程结构的震害评估问题,特别是补充近断层区域无观测台站处的地震动,本文提出一种基于近断层实测数据和等效脉冲模型的近断层地震动复原方法。该方法通过近断层实测地震动反应谱的插值来生成近断层区域无观测台站处的地震动,再利用经验等效脉冲模型恢复地震动的速度脉冲和永久位移特征。以我国台湾集集地震为例给出了近断层区域两个典型位置的地震动复原示例,通过与实测地震动记录进行对比,验证了本文方法的有效性和合理性。研究表明,本文方法能够构造具有近断层脉冲型地震动特征的地震动,并能够复原近断层区域无实测数据的站点处的地震动,可为近断层区域缺失实测数据的地震动的需求提供一种实用方法。

Abstract:

Near-fault ground motions are critical for assessing seismic damage. However, recorded near-fault ground motion during an earthquake is often limited. To address the challenge of evaluating seismic damage to engineering structures in near-fault regions, particularly for supplementing ground motion at sites without observing stations in near-fault regions, this study proposed a near-fault ground motion reconstruction method based on observed data and an equivalent pulse model. The method initially generated ground motion at sites without observing stations in near-fault regions by interpolating response spectra from observed near-fault ground motion. Subsequently, it employed an empirical equivalent pulse model to recover velocity pulses and permanent displacements of ground motion. By taking the Chi-Chi earthquake in Taiwan, China as an example, examples of ground motion reconstruction at two typical locations in the near-fault region were provided. By comparing them with the observed ground motion data, the effectiveness and rationality of the method were validated. The results demonstrate that the method effectively reconstructs ground motions with near-fault pulse-like characteristics and ground motion at sites without observed data in near-fault regions. This offers a practical approach to meet the need for ground motion in near-fault regions where observed data are lacking.