Abstract The 2016–2017 seismic sequence in the Central Apennines (Italy) demonstrated, once again, the relevant role of the differentiated seismic effects related to different features in complex geological contexts at a short distance (i.e. soft sediment-filled valley, hilly relieves, complex buried geometries). The heavy damages of old settlements located on the top of a rocky hill, such as Arquata del Tronto hill, raised the question on the main role of three-dimensional movements of asymmetrical isolated rocky reliefs in generating disruptions during the seismic shaking. In order to shed light on these effects, the writing authors analysed the seismic response of a digital 3D model of the Arquata del Tronto hill, that was constructed by considering the topography and the underground geological settings of the area. The seismic response was evaluated through 3D numerical simulations of seismic waves propagation with the spectral element method for the period range 0.1–1 s, that covers the typical resonance frequencies of the buildings involved in the studied case. The obtained results explain the recorded strong motion at Arquata site and are consistent with the observed heterogeneous damage distribution. This study evidences the need for accurate 3D models in the evaluation of the seismic response of ridges with topographic and geological asymmetries and demonstrates that the common usage of 2D simplified simulations to approximate the 3D seismic behaviour is not correct. Additionally, the study points out the paramount role that the characterization in engineering - geological terms plays in the numerical 3D simulation of the seismic site response. Thus, in microzoning studies, simplifications related to both dimensional and geo-litho-seismic characterizations should be avoided.

中文翻译：

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用于解释地震微带化岩石山丘地形效应的 3D 数值模型：Arquata del Tronto 村庄的案例研究

摘要 2016-2017 年中部亚平宁山脉（意大利）地震序列再次证明了与复杂地质背景下短距离（即软沉积物填充谷、丘陵起伏、复杂的埋藏几何形状）。Arquata del Tronto 山等岩石山顶上的旧定居点遭到严重破坏，引发了关于不对称孤立岩石地貌的三维运动在地震震动过程中产生破坏的主要作用的问题。为了阐明这些影响，作者分析了 Arquata del Tronto 山的数字 3D 模型的地震响应，该模型是通过考虑该地区的地形和地下地质环境而构建的。地震响应是通过地震波传播的 3D 数值模拟来评估的，使用频谱元素方法在 0.1-1 秒的周期范围内，涵盖了所研究案例中涉及的建筑物的典型共振频率。获得的结果解释了 Arquata 站点记录的强运动，并与观察到的不均匀损伤分布一致。这项研究证明了在评估具有地形和地质不对称性的山脊的地震响应时需要精确的 3D 模型，并证明通常使用 2D 简化模拟来近似 3D 地震行为是不正确的。此外，该研究还指出了工程 - 地质术语中的表征在地震现场响应的数值 3D 模拟中起着至关重要的作用。因此，