Variable-resolution building exposure modelling for earthquake and tsunami scenario-based risk assessment: an application case in Lima, Peru
Variable-resolution building exposure modelling for earthquake and tsunami scenario-based risk assessment: an application case in Lima, Peru
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DOI：
10.5194/nhess-21-3599-2021
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发表时间：
2021-11-26
影响因子：
4.6
通讯作者：
Babeyko, Andrey
中科院分区：
文献类型：
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作者：
Gomez-Zapata, Juan Camilo;Brinckmann, Nils;Babeyko, Andrey
我们建议使用可变分辨率边界的基础上，中央Voronoi镶嵌（CVTs）空间聚合建筑物暴露模型的风险评估，以各种自然灾害。当所考虑的灾害的空间分布呈现出具有对比足迹和空间相关性的强度度量时，例如在沿海环境中，这种框架特别有益。这项工作避免了一个不正确的假设，即一个单一的强度值，从灾害与低空间相关性（如海啸）可以被认为是具有代表性的大型地理单元内的物理脆弱性评估，没有，在同一时间，增加了整个模型的复杂性。我们提出了解耦的地震和海啸的风险估计为基础的住宅建筑库存的利马（秘鲁）。我们观察到，远场俯冲源的地震损失模型实际上对曝光分辨率不敏感。相反，海啸损失模型和相关的不确定性取决于灾害强度的空间相关性以及暴露模型的分辨率。我们注意到，位于沿海地区的投资组合暴露在利马的两个危险，地面震动占主导地位的损失较低的地震，而海啸造成的损失最大的规模较大的事件。对于后者，使用两套现有的经验流深脆弱性模型，导致计算的损失有很大的差异。因此，这项研究提高了人们对与选择脆弱性模型和用于风险建模和损失绘图的空间聚集实体有关的不确定性的认识。
We propose the use of variable resolution boundaries based on central Voronoi tessellations (CVTs) to spatially aggregate building exposure models for risk assessment to various natural hazards. Such a framework is especially beneficial when the spatial distribution of the considered hazards presents intensity measures with contrasting footprints and spatial correlations, such as in coastal environments. This work avoids the incorrect assumption that a single intensity value from hazards with low spatial correlation (e.g. tsunami) can be considered to be representative within large-sized geo-cells for physical vulnerability assessment, without, at the same time, increasing the complexity of the overall model. We present decoupled earthquake and tsunami scenario-based risk estimates for the residential building stock of Lima (Peru). We observe that earthquake loss models for far-field subduction sources are practically insensitive to the exposure resolution. Conversely, tsunami loss models and associated uncertainties depend on the spatial correlations of the hazard intensities as well as on the resolution of the exposure models. We note that for the portfolio located in the coastal area exposed to both perils in Lima, the ground shaking dominates the losses for lower-magnitude earthquakes, whilst tsunamis cause the most damage for larger-magnitude events. For the latter, two sets of existing empirical flow depth fragility models are used, resulting in large differences in the calculated losses. This study, therefore, raises awareness about the uncertainties associated with the selection of fragility models and spatial aggregation entities for exposure modelling and loss mapping.