The hazards of unconfined pyroclastic density currents: A new synthesis and classification according to their deposits, dynamics, and thermal and impact characteristics
The hazards of unconfined pyroclastic density currents: A new synthesis and classification according to their deposits, dynamics, and thermal and impact characteristics
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DOI：
10.1016/j.jvolgeores.2021.107429
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发表时间：
2021-12-20
影响因子：
2.9
通讯作者：
Baxter, Peter J.
中科院分区：
文献类型：
--
作者：
Lerner, Geoffrey A.;Jenkins, Susanna F.;Baxter, Peter J.
火山碎屑密度流（PDCs）是最危险的火山灾害之一。这些不受限制的PDCs能够淹没可能对这些危害毫无准备的居民区，造成重大生命损失和基础设施破坏。尽管它们能够造成严重的影响，但以前只在有限数量的具体案例研究中描述了无限制的PDCs。在这里，我们进行了更广泛的比较研究，回顾了不同类型的无承压pdc，它们的沉积，动力学和影响，以及每个元素之间的关系。无约束多氯联苯存在于一定的浓度、速度和温度范围内，这些特性对确定其影响很重要。我们定义了四种端元无约束PDCs：快速溢出流量，2。缓慢溢出流量；高能浪涌，4。低能量分离浪涌（led），并回顾历史上每一次爆发的特征和事件。这四个端元都是在2010年印度尼西亚默拉皮火山喷发序列中观测到的。我们将这次充分研究的火山喷发作为案例研究，重点关注Bakalan村（火山以南13公里）和Bronggang村（火山以南14公里），这两个村庄分别受到缓慢溢出流和led的影响。这两种无约束PDC类型是以往火山喷发中描述最少的，但在2010年默拉皮火山喷发期间，溢流导致建筑物被毁，led造成重大生命损失。我们讨论了这些无约束PDCs的动力学和沉积，以及由此产生的影响。然后，我们利用从2010年默拉皮火山喷发中吸取的教训，评估了与2018年危地马拉富埃戈火山致命喷发相关的一些影响。利用补充实地工作的卫星图像和媒体图像来确定是否存在溢流和发光二极管，这些溢流和发光二极管在距离山顶9公里的被淹没地区造成数百人丧生，数百座建筑物被毁。通过对无侧限PDC特征、动力学和影响进行编目，我们旨在强调在活火山应急管理和规划中考虑此类现象的重要性和价值。(C) 2021作者。Elsevier B.V.出版
Pyroclastic density currents (PDCs) that escape their confining channels are among themost dangerous of volcanic hazards. These unconfined PDCs are capable of inundating inhabited areas thatmay be unprepared for these hazards, resulting in significant loss of life and damage to infrastructure. Despite their ability to cause serious impacts, unconfined PDCs have previously only been described for a limited number of specific case studies. Here, we carry out a broader comparative study that reviews the different types of unconfined PDCs, their deposits, dynamics and impacts, aswell as the relationships between each element. Unconfined PDCs exist within a range of concentration, velocity and temperature: characteristics that are important in determining their impact. We define four end-member unconfined PDCs: 1. fast overspill flows, 2. slow overspill flows, 3. high-energy surges, and 4. low-energy detached surges (LEDS), and review characteristics and incidents of each from historical eruptions. These four end-members were all observed within the 2010 eruptive sequence of Merapi, Indonesia. Weuse this well-studied eruption as a case study, focusing on the villages of Bakalan (13 km south of the volcano) and Bronggang (14 km south of the volcano), which were impacted by slow overspill flows and LEDS, respectively. These two unconfined PDC types are the least described from previous volcanic eruptions, but during the 2010 Merapi eruption the overspill flows resulted in building destruction and the LEDS in significant loss of life. We discuss the dynamics and deposits of these unconfined PDCs, and the resultant impacts. We then use the lessons learned from the 2010 Merapi eruption to assess some of the impacts associated with the deadly 2018 Fuego, Guatemala eruption. Satellite imagery and media images supplementing fieldwork were used to determine the presence of both overspill flows and LEDS, which resulted in the loss of hundreds of lives and the destruction of hundreds of buildings in inundated areas within 9 km of the summit. By cataloguing unconfined PDC characteristics, dynamics and impacts, we aimto highlight the importance and value of accounting for such phenomena in emergency management and planning at active volcanoes. (C) 2021 The Authors. Published by Elsevier B.V.