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

位于智利中部的拉古纳德尔毛勒火山田目前正在以有史以来在非活跃喷发的火山中测量到的最快速度上升。在过去的2万年里，拉古纳德尔毛勒的火山活动一直由流纹岩主导，这是一种罕见的火山岩，通常会爆发。新近流纹岩的分布和组成表明，它们是一个持续至今的大型浅层岩浆储层的产物。为了理解正在进行的隆起和未来潜在的大规模爆炸性喷发之间的关系，刻画最近一次火山活动之前的岩浆动力学特征是至关重要的。最新流纹岩中结晶的矿物组成记录了拉古纳德尔毛勒岩浆储层温度、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，并利用数值模型来估计相对于随后喷发的岩浆储层状态变化的时间。这项研究将在新加坡南洋理工大学与应用这些数值模拟技术的先驱Fidel Costa博士合作进行。斜长石和石英成分将使用电子探针和LA-ICP-MS进行测量。测量具有不同扩散系数的多种微量元素将提供最准确的相对年龄。基性岩浆侵入拉古纳德尔莫勒浅层硅质岩浆系统，可能导致了观测到的矿物分带，引发了最近的火山喷发，并推动了持续的动荡。了解对此类事件的动态响应对于评估拉古纳德尔毛勒火山危险性以及大量流纹岩岩浆储层的聚集和最终喷发至关重要。该奖项由美国国家科学基金会与新加坡国家研究基金会共同资助。

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.