Aluto volcano, in the Main Ethiopian Rift, is a peralkaline caldera system, which comprises conglomerations of rhyolite (obsidian) lavas and enigmatic pumice cones. Recent work at Aluto has found that pumice cone eruptions are highly unsteady, and form convective eruption plumes that frequently collapse to generate pyroclastic density currents (PDCs). We develop a methodology and present results for the first probabilistic volcanic hazard assessment (PVHA) for PDCs at a pumice cone volcano. By doing so, we estimate the conditional probability of inundation by PDCs around Aluto volcano, incorporating the aleatory uncertainty in PDC hazard. We employ a Monte Carlo energy cone modeling approach, which benefits from parameterization informed by field investigations and volcanic plume modeling. We find that despite the relatively modest eruptions that are likely to occur, the wide distribution of past vent locations (and thus the high uncertainty of where future vents might open), results in a broad area being potentially at risk of inundation by PDCs. However, the aleatory uncertainty in vent opening means that the conditional probabilities are lower (≤ 0.12), and more homogeneous, over the hazard domain compared to central-vent volcanoes (where conditional probabilities are often ≤ 1 close to the vent). Despite this, numerous settlements, amenities, and economically valuable geothermal infrastructure, lie within the most hazardous (P(PDC|eruption) ≥ 0.05) regions of Aluto caldera. The Monte Carlo energy cone modeling approach provides a quantitative, accountable and defendable background and long-term PVHA for PDCs from Aluto. These results could be combined in the future with hazard assessments relating to tephra fall and/or lava to develop a comprehensive volcanic hazard map for the caldera. Following appropriate parameterization, the approach developed here can also be used to compute a PDC PVHA at other volcanoes where vent location is uncertain.

埃塞俄比亚主裂谷中的Aluto火山是一种高碱性火山口系统，由流纹岩（黑曜石）熔岩和神秘的浮石组成。Aluto的最新研究发现，浮石的喷发高度不稳定，并形成对流喷发羽，经常塌陷以产生火山碎屑密度流（PDC）。我们开发了一种方法，并为浮石锥火山的PDC提供了首次概率性火山危害评估（PVHA）的结果。通过这样做，我们结合了PDC危险的不确定性，估计了Aluto火山周围PDC淹没的条件概率。我们采用了蒙特卡洛能量锥建模方法，该方法得益于现场调查和火山羽建模所提供的参数设置。我们发现，尽管可能会发生相对较小的喷发，但过去通风口的位置分布较广（因此未来通风口可能在何处打开的不确定性很高），导致大面积地区有被PDC淹没的风险。然而，与中央通风口的火山（条件通风口附近的条件机率通常≤1）相比，通风口打开时的不确定性意味着在危险域内的条件机率较低（≤0.12），并且更加均匀。尽管如此，在最危险的区域内仍存在许多居民点，便利设施和具有经济价值的地热基础设施（然而，与中央通风口的火山（条件通风口附近的条件机率通常≤1）相比，通风口打开时的不确定性意味着在危险域内的条件机率较低（≤0.12），并且更加均匀。尽管如此，在最危险的区域内仍存在许多居民点，便利设施和具有经济价值的地热基础设施（然而，与中央通风口的火山（条件通风口附近的条件机率通常≤1）相比，通风口打开时的不确定性意味着在危险域内的条件机率较低（≤0.12），并且更加均匀。尽管如此，在最危险的区域内仍存在许多居民点，便利设施和具有经济价值的地热基础设施（P（PDC|喷发）≥0.05）Aluto破火山口区域。蒙特卡洛能量锥建模方法可为Aluto的PDC提供定量，负责和可辩护的背景以及长期PVHA。将来，这些结果可以与与特非拉瀑布和/或熔岩有关的危害评估相结合，从而为破火山口开发出全面的火山危害图。经过适当的参数设置后，此处开发的方法还可以用于计算其他火山口位置不确定的PDC PVHA。