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

卡尔布科火山位于智利南部人口稠密的洛斯拉各斯地区（南纬41度19'48“、西经72度37'06”），是一座海拔2015米、冰川覆盖的层状火山，历史上曾在1893-95年、1906-7年、1911-12年、1917年、1932年、1945年、1961年和1972年发生过非常大的火山喷发。2015年4月22日，Calbuco在18:04经历了一次90分钟的强大喷发，随后分别在4月23日和30日的01:00和13:10发生了两次大喷发，导致6500人撤离，并实施了半径20公里的隔离区。这些喷发产生的火山灰高达15公里，给卡尔布科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）下降到几个河流集水区，从火山辐射出来，转化为热洪水和沉积物，被称为火山泥流，传播距离长达14公里，到达周围的人口稠密地区，对基础设施和财产造成了广泛的破坏。尽管卡尔布科火山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，即使冰川冰量很小的火山也能产生大量的火山泥流。我们的科学目标是确定正在进行的卡尔布科火山喷发期间产生的火山泥流的原因、动力学和影响。为了实现我们的目标，我们将在实际可能的情况下尽快对火山进行实地考察。在实地考察中，我们将对火山泥流对卡尔布科周围河谷系统的直接地貌和沉积影响进行分类。我们将识别火山泥流冲刷痕迹，并将使用差分卫星定位系统和地面激光扫描来调查这些痕迹。我们将用直升机对火山泥流通道进行激光扫描调查，还将使用机载雷达来确定火山爆发后山上遗留的冰的存在和厚度。我们将取样并详细描述这些新火山泥流沉积物的垂直特征。卡尔布科火山喷发提供了一个难得的机会来研究罕见的热火山泥流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火山泥流开始之前尽快进行实地调查，这些火山泥流可能掩盖了这些早期事件的特征。我们的研究将有助于更好地了解危险的火山泥流过程，并希望减少对人口的风险。

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.