Ground motion is computed at the historical center of Napoli for the 5 December 1456 and 5 June 1688 earthquakes responsible for VIII maximum felt intensity (MCS scale). Computations are performed using the hybrid technique, which is based on the mode summation and finite difference methods. These consider the source, propagation and local site effects. The approach is fully justified by the detailed knowledge of the physical parameters of the local subsoil based on the models inferred from noise cross-correlation measurements between two receivers. Moreover, the propagation model is validated through the fitting of synthetics with recording of a moderate earthquake at the historical center of Napoli (29 December 2013, M W = 5.2) close to the seismogenic fault responsible for the 1688 earthquake. Ground motion is computed along a two-dimensional section crossing the historical center for the seismogenic sources as known from the literature. A consistency exists between the computed peak ground acceleration and intensity data if we attribute higher moment magnitudes of 7 to the 1688 earthquake and 7.3–7.4 for the 1456 earthquake. In light of the uncertainties related to the macroseismic intensities and estimated magnitudes of these historical events and the relevant masonry heritage of the historical center of Napoli, the highest values of the computed ground motion are suggested for seismic retrofitting of the masonry heritage. A scenario earthquake like those of 1688 ( M W = 7) and 5 December 1456 ( M W = 7.4) is predicted by the seismic code for limit states of life safety or collapse, depending on the site and the true material damping.

中文翻译：

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1456 年和 1688 年那不勒斯（意大利南部）历史中心的地面震动情景

计算那不勒斯历史中心 1456 年 12 月 5 日和 1688 年 6 月 5 日地震的地面运动，该地震导致 VIII 最大有感强度（MCS 等级）。使用混合技术进行计算，该技术基于模态求和和有限差分方法。这些考虑了源、传播和本地站点效应。基于从两个接收器之间的噪声互相关测量推断出的模型，当地底土的物理参数的详细知识充分证明了该方法的合理性。此外，通过对那不勒斯历史中心（2013 年 12 月 29 日，MW = 5.2）靠近导致 1688 年地震的发震断层的中等地震记录进行合成拟合，验证了传播模型。如文献中所知，地震动是沿着穿过历史发震源中心的二维剖面计算的。如果我们将 7 的更高矩震级归因于 1688 年的地震和 7.3-7.4 的 1456 年地震，则计算出的峰值地面加速度和强度数据之间存在一致性。鉴于与这些历史事件的宏观地震强度和估计震级以及那不勒斯历史中心的相关砌体遗产相关的不确定性，建议对砌体遗产进行地震改造时计算出的地面运动的最高值。根据现场和真实材料阻尼，地震规范预测了生命安全或倒塌的极限状态，如 1688 年 (MW = 7) 和 1456 年 12 月 5 日 (MW = 7.4) 的情景地震。