EAPSI: Investigating large, explosive volcanic eruption in the Chilean Andes

位于智利中部的拉古纳德尔莫勒火山场目前正在以有史以来非活跃喷发的火山测量到的最快的速度上升。在过去的两万年里，毛勒湖的火山活动一直以流纹岩为主，流纹岩是一种罕见的火山岩，通常会爆发。现代流纹岩的分布和成分表明，它们是一个大型浅层岩浆储集层的产物，该储集层一直持续到今天。为了了解正在进行的隆起和未来可能发生的大规模爆炸性喷发之间的关系，关键是要确定最近一次火山活动之前的岩浆动力学特征。在最近的流纹岩中结晶的矿物成分记录了拉古纳德尔毛勒岩浆储集层的温度、压力和化学成分的变化。这项研究将包括测量单个晶体内的成分变化，并利用数值模型估计岩浆库状态相对于随后喷发的变化的时间。这项研究将在新加坡南洋理工大学与菲德尔·科斯塔博士合作进行，菲德尔·科斯塔博士是应用这些数值建模技术的先驱。斜长石和石英的成分将用电子探针和LA-ICPMS进行测量。测量具有不同扩散系数的多种痕量元素将提供最准确的相对年龄。镁铁质岩浆侵入位于拉古纳德尔莫勒的浅层硅质岩浆系统，可能导致了观察到的矿物分带，引发了最近的喷发，并正在推动正在进行的动乱。了解对这类事件的动态响应对于评估德尔毛勒湖的火山灾害以及大量流纹岩岩浆储集层的组装和最终喷发至关重要。该NSF EAPSI奖是与新加坡国家研究基金会合作资助的。

The Laguna del Maule volcanic field, located in central Chile, is currently uplifting at a rate among the fastest ever measured at a volcano that is not actively erupting. For the last 20 thousand years, volcanism at Laguna del Maule has been dominated by rhyolite, an uncommon volcanic rock that commonly erupts explosively. The distribution and compositions of recent rhyolites suggest that they are the product of a large, shallow magma reservoir that persists to this day. To understand the relationship between the ongoing uplift and a future potentially large, explosive eruption, it is critical to characterize the magma dynamics that preceded the most recent volcanism. The composition of minerals crystallized in the most recent rhyolites record the changing temperature, pressure, and chemistry of the Laguna del Maule magma reservoir. This research will consist of measuring compositional variation within individual crystals and utilizing numerical models to estimate the timing of the changes in the state of the magma reservoir relative to the subsequent eruption. This research will be performed at the Nanyang Technological University in Singapore in collaboration with Dr. Fidel Costa, a pioneer in applying these numerical modeling techniques. Plagioclase and quartz compositions will be measured using electron microprobe and LA-ICP-MS. The measurement of multiple trace elements with varying diffusivities will provide the most accurate relative ages. The intrusion of mafic magma into the shallow silicic magma system at Laguna del Maule could potentially have imparted the observed mineral zonation, triggered the recent eruptions, and be driving the ongoing unrest. Understanding the dynamic response to such and event is critical to assessing the volcanic hazard at Laguna del Maule and the assembly and eventual eruptions of voluminous rhyolitic magma reservoirs. This NSF EAPSI award is funded in collaboration with the National Research Foundation of Singapore.