Ground‐Motion Observations at Hotel Montana during the M 7.0 2010 Haiti Earthquake: Topography or Soil Amplification?
Ground‐Motion Observations at Hotel Montana during the M 7.0 2010 Haiti Earthquake: Topography or Soil Amplification?
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DOI：
10.1785/0120120242
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发表时间：
2013-10
影响因子：
3
通讯作者：
D. Assimaki;S. Jeong
中科院分区：
文献类型：
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作者：
D. Assimaki;S. Jeong
据报道，2010年海地7.0级地震期间，位于佩蒂翁维尔区山脊顶部的蒙大拿酒店附近发生了异常严重的结构性破坏。根据观测结果，美国地质调查局部署了地震站，余震记录表明，与参考场地条件下的相邻台站相比，山顶上的地面运动放大。地形起伏的存在已被证明是显着加剧的后果，强地面运动在过去的事件，地形效应被提出来解释的意见。在本文中，我们测试的假设，地形放大的主导因素，有助于在蒙大拿酒店附近的损害集中。我们最初进行数值模拟的山脊地震响应假设弹性均匀的场地条件下，并显示，数值预测的地形放大不同意与现场数据的振幅和频率。相反，虽然山顶场地条件的一维地面响应分析预测了与现场数据相同频率范围内的放大，但它们显著低估了记录的振幅。然后，我们进行数值模拟的山麓山脊响应地震运动，同时考虑土壤分层，并定性地证明，记录的放大最有可能归因于耦合的网站地形放大效应，即地震波被困在软土层的近表面，放大的结果，混响，并且由于入射到不规则地面上时的衍射和散射而被进一步修改。地形-土壤放大耦合效应的参数调查，然后进行，我们的研究结果表明，当占一个假设的土壤-基岩界面在100米的深度，预测与观察到的运动非常吻合。
Unusually severe structural damage was reported during the 2010 M 7.0 Haiti earthquake in the vicinity of Hotel Montana, located on top of a ridge in the district of Petionville. Prompted by the observations, U.S. Geological Survey seismic stations were deployed, and aftershock recordings indicated ground‐motion amplification on the top of the hill compared to adjacent stations on reference site conditions. The presence of topographic relief has been shown to significantly aggravate the consequences of strong ground motion during past events, and topographic effects were brought forward to explain the observations. In this paper, we test the hypothesis of topographic amplification as the dominant factor that contributed to the damage concentration in the vicinity of Hotel Montana. We initially conduct numerical simulations of the ridge seismic response assuming elastic homogeneous site conditions, and show that numerical predictions of topographic amplification disagree with the field data both in amplitude and in frequency. Conversely, while 1D ground‐response analyses for the site conditions at the hilltop predict amplification in the same frequency range as the field data, they significantly underestimate the recorded amplitude. We then conduct numerical simulations of the foothill ridge response to seismic motion while accounting for soil layering, and qualitatively demonstrate that the recorded amplification is most likely attributed to coupled site–topographic amplification effects, namely to seismic waves trapped in the soft soil layers of the near surface, amplified as a consequence of reverberations, and further modified due to diffraction and scattering upon incidence on the irregular ground surface. Parametric investigations of the topography–soil amplification coupling effects are then conducted, and our results show that when accounting for a hypothetical soil–bedrock interface at 100 m depth, predictions are in excellent agreement with the observed motion.