When assessing seismic risk at a city scale, local site conditions can significantly modify the destructive potential of an earthquake. This was the case in Mexico City in 1985 and 2017, which is located on a sedimentary valley. For that reason, characterization and consideration of these site effects, in addition to assessing the probability of occurrence of a destructive earthquake in a given region, are crucial. For this purpose, a tri-dimensional model was developed using a numerical code that permits to carry out such kind of studies. The code is based on the spectral element method allowing solving the waves propagation problem in tri-dimensional solid media. The seismic phenomenon is simulated in its entirety: from the seismic source to the site using a representative model of the complexity of the wave path. However, this introduces uncertainties that must be quantified, controlled and reduced by validating the results of the numerical tool with measurements on a real study site. This work aims to study numerically the effect of the geometric structure of soil and subsoil on the prediction of ground motion at the regional scale. The first obtained results show the importance of the in situ measures on the regional-scale simulations.

在评估城市规模的地震风险时，当地的现场条件可能会大大改变地震的破坏力。1985年和2017年的墨西哥城就是这样，它位于一个沉积谷地上。因此，除了评估给定区域发生破坏性地震的可能性外，表征和考虑这些场地影响也至关重要。为此目的，使用允许进行此类研究的数字代码开发了三维模型。该代码基于频谱元素方法，可以解决三维固体介质中的波传播问题。地震现象是完整模拟的：使用地震波路径复杂性的代表性模型，从地震源到现场。然而，这就引入了不确定性，这些不确定性必须通过在实际研究现场通过测量验证数值工具的结果来量化，控制和减少。这项工作旨在从数值上研究土壤和地下土壤的几何结构对区域尺度地面运动预测的影响。最初获得的结果表明，就地测量对区域尺度模拟的重要性。