Causes, and impacts of lahars generated by the April, 2015 eruption of Calbuco volcano, Chile

卡尔布哥火山位于智利南部人口稠密的洛斯拉各斯地区(西经41度19‘48“S 72度37’06”)，高2015米，有冰川覆盖的层状火山，有1893-95年、1906-7年、1911-12年、1917年、1932年、1945年、1961年和1972年的超大规模火山喷发历史。2015年4月22日，卡尔布哥在18时04分经历了90分钟的强烈喷发，随后分别在4月23日和30日1时00分和13时10分经历了更多的大喷发，导致6500人疏散，并设立了半径20公里的隔离区。这些喷发产生了高达15公里的火山灰羽流，对卡尔布哥东北部造成了广泛的破坏和财产损失。炽热的火山碎屑流(发光的雪崩)流入火山辐射的几个河流集水区，转化为被称为拉哈尔的热水和沉积物洪水，传播距离长达14公里，到达周围人口稠密的地区，对基础设施和财产造成广泛破坏。尽管卡尔布哥和附近安第斯山脉的其他冰川火山最近经历了冰川规模的缩小，但目前的喷发表明，即使是冰川体积较小的火山也可以产生大量的冰川。我们的科学目标是确定在正在进行的卡尔布哥喷发期间产生的拉哈尔的原因、动力学和影响。为了实现我们的目标，我们将尽可能快地对火山进行实地考察。在实地考察中，我们将对喀尔布哥周围的河谷系统产生的直接地貌和沉积影响进行编目。我们将使用差动卫星定位系统和地面激光扫描来识别湖水洗痕迹，并对这些痕迹进行调查。我们将对拉哈尔海峡进行一次基于直升机的激光扫描调查，并将使用机载雷达来确定这些喷发后山上是否存在冰层和冰的厚度。我们将对这些新鲜岩浆矿床的垂直特征进行详细的取样和描述。卡尔布哥火山喷发提供了一个特殊的机会来研究罕见的热岩浆的动力学和沉积特征，因为它们仍在冷却和脱气。我们计划在随后的火山和降雨引发的可能掩盖这些早期事件特征的火山爆发之前尽快进行实地考察。我们的研究将有助于更好地了解有害的熔岩过程，希望降低对人口的风险。

Calbuco is a 2015m high, glacier capped, stratovolcano in the heavily populated Los Lagos district of southern Chile (41 degrees 19'48"S 72 degrees 37'06"W) with a history of very large volcanic eruptions in 1893-95, 1906-7, 1911-12, 1917, 1932, 1945, 1961 and 1972. On 22 April, 2015 Calbuco experienced a powerful 90 minute eruption at 18:04h followed by additional major eruptions at 01:00h and 13:10h on 23 & 30 April, respectively, resulting in the evacuation of 6500 people and the imposition of a 20 km radius exclusion zone. These eruptions generated ash plumes up to 15 km high, causing widespread disruption and damage to property to the NE of Calbuco. Hot pyroclastic flows (glowing avalanches) descended into several river catchments radiating from the volcano transforming into hot floods of water and sediment known as lahars which travelled distances of up to 14 km, reaching surrounding populated areas resulting in extensive damage to infrastructure and property. Although Calbuco, along with other nearby glaciated volcanoes in the Andes, has experienced recent reductions in the size of its glaciers, the current eruption indicates that even volcanoes with small glacier ice volumes can generate significant lahars. Our scientific goal is to determine the causes, dynamics and impacts of lahars generated during the ongoing Calbuco eruption. To achieve our goals we will undertake fieldwork on the volcano as soon as is practically possible. In the field we'll catalogue the immediate geomorphic and sedimentary impact of lahars on the river valleys systems surrounding Calbuco. We'll Identify lahar wash marks and will survey these use differential satellite positioning systems and ground based laser scanning. We'll conduct a helicopter based laser scanning survey of the lahar channels and will also use an airborne Radar to determine the presence and thickness of any ice left on the mountain after these eruptions. We'll sample and describe the vertical characteristics of these fresh lahar deposits in detail. The Calbuco eruption provides an exceptional opportunity to examine the dynamics and sedimentary signature of rare hot lahars, as they are still cooling and degassing. We plan to conduct fieldwork as soon as possible before the onset of subsequent volcanic and rainfall-induced lahars which may mask the signature of these earlier events. Our research will contribute to a better understanding of hazardous lahar processes with the hope of reducing the risk to population.