Abstract Over the past decades, researchers have given increasing attention to the modelling of the spatial correlation of earthquake ground motion intensity measures (IMs), particularly when the seismic risk of spatially distributed systems is being assessed. The quantification of the seismic performance of these systems requires the estimation of simultaneous IMs at multiple locations during the same earthquake, for which the correlation between pairs of locations needs to be defined. Numerous spatial correlation models of common IMs, such as peak ground acceleration and spectral acceleration, have been published. Although the functional forms of the models are generally similar, significant discrepancies exist in terms of the rate of decay of the correlation with increasing inter-site separation distance. The main reasons for such differences lie with the selected databases, the ground-motion models used to derive the spatial correlation models, estimation approaches and regional geological conditions. In this study, we aim to provide a comprehensive review of spatial correlation models, analysing factors that most affect the spatial dependency of IMs. We use strong-motion records from the 2016–2017 Central Italy earthquake sequence combined with ground-motion simulations to examine the influence of various factors on spatial correlation models. We investigate the dependency on: (1) the estimation method and model fitting technique; (2) the magnitude; (3) the response-spectral period; and (4) local-soil conditions. Our results suggest that the rate of decay is not only period-dependent, but also regionally-dependent, so that a single universal correlation model based on large datasets is not appropriate when describing the correlation behaviour of small geographical areas. Our outcomes could be used to guide the development of new spatial correlation models.

中文翻译：

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模拟地震地震动的空间相关性：来自文献的见解、来自 2016-2017 年意大利中部地震序列和地面运动模拟的数据

摘要 在过去的几十年里，研究人员越来越关注地震地震动强度测量 (IM) 的空间相关性建模，特别是在评估空间分布式系统的地震风险时。量化这些系统的抗震性能需要估计同一地震期间多个位置的同时发生的 IM，为此需要定义成对位置之间的相关性。已经发表了许多常见 IM 的空间相关模型，例如峰值地面加速度和谱加速度。尽管模型的函数形式大体相似，但在相关性随站点间间隔距离增加的衰减率方面存在显着差异。造成这种差异的主要原因在于所选择的数据库、用于推导空间相关模型的地震动模型、估计方法和区域地质条件。在本研究中，我们旨在全面回顾空间相关模型，分析最影响 IM 空间依赖性的因素。我们使用 2016-2017 年意大利中部地震序列的强震记录结合地面运动模拟来检查各种因素对空间相关模型的影响。我们调查依赖于：（1）估计方法和模型拟合技术；(2) 量级；(3)反应谱期；(4) 当地土壤条件。我们的结果表明衰减率不仅与时期有关，而且与区域有关，因此，在描述小地理区域的相关行为时，基于大数据集的单一通用相关模型是不合适的。我们的结果可用于指导新空间相关模型的开发。