Towards Quantitative Volcanic Risk of Pyroclastic Density Currents: Probabilistic Hazard Curves and Maps Around Somma‐Vesuvius (Italy)
Towards Quantitative Volcanic Risk of Pyroclastic Density Currents: Probabilistic Hazard Curves and Maps Around Somma‐Vesuvius (Italy)
复制标题
火山碎屑密度流的定量火山风险：索马-维苏威火山周围的概率危险曲线和地图（意大利）
DOI：
10.1029/2017jb015383
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
A. Patra
中科院分区：
文献类型：
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作者：
Pablo Tierz;E. R. Stefanescu;L. Sandri;R. Sulpizio;G. Valentine;W. Marzocchi;A. Patra
火山碎屑密度流（PDCs）是气体和火山碎屑的热流动混合物，可导致火山爆发周围广泛的生命损失和结构破坏。危险评估，包括量化的偶然性和认识的不确定性是一个必要的步骤，以准确和完整的方式计算火山风险的PDCs。我们开发了一个三阶段的程序来量化密集PDC的不确定性。首先，TITAN 2D模型参数化模拟PDC现象在目标火山。其次，TITAN 2D与多项式混沌求积相结合，将偶然的不确定性从模型参数传播到灾害强度测量（流深和速度）。第三，TITAN 2D-PCQ分析与火山灾害的贝叶斯事件树合并，以包括其他火山特有的偶然不确定性和认识不确定性的估计。通过这种方法获得了火山周围的流深和速度的概率风险曲线和地图的全面集合，并在Somma‐Vesuvius（意大利）说明了其应用。我们的研究结果表明，从目前的中央火山口，喷发的概率约为30%（偶然的不确定性）和10%和60%之间（偶然和认识的不确定性），流深= 1米，流速= 2米/秒，在第一个2-3公里的喷口周围。速度超过30米/秒的密集PDC可能覆盖喷口周围约50平方公里的区域，平均每10次喷发就有1次。这种类型的概率危险评估是朝着Somma-Vesuvius和全球密集PDC的定量火山风险迈出的关键一步。
Pyroclastic density currents (PDCs) are hot flowing mixtures of gas and pyroclasts that can cause widespread loss of life and structural damage around the erupting volcano. Hazard assessments that include quantification of aleatory and epistemic uncertainty are a necessary step toward calculating volcanic risk of PDCs in an accurate and complete manner. We develop a three‐stage procedure to quantify such uncertainties for dense PDCs. First, the TITAN2D model is parameterized to simulate the PDC phenomenology at the target volcano. Second, TITAN2D is coupled with Polynomial Chaos Quadrature to propagate aleatory uncertainty from model parameters to hazard intensity measures (flow depth and speed). Third, the TITAN2D‐PCQ analysis is merged with the Bayesian Event Tree for Volcanic Hazard to include other volcano‐specific aleatory uncertainty and estimates of epistemic uncertainty. A comprehensive collection of probabilistic hazard curves and maps for flow depth and speed around the volcano is obtained through this methodology and its application is illustrated at Somma‐Vesuvius (Italy). Our results indicate that, given an eruption from the current central crater, exceedance probabilities are around 30% (aleatory uncertainty only) and between 10% and 60% (aleatory and epistemic uncertainty), for flow depth = 1 m and flow speed = 2 m/s, over the first 2–3 km around the vent. Dense PDCs faster than 30 m/s may cover areas about 50 km2 around the vent, on average, 1 every 10 eruptions. This type of probabilistic hazard assessment represents a crucial step toward quantitative volcanic risk of dense PDCs at Somma‐Vesuvius and worldwide.