Physical Aspects of Magma Degassing - An Accomplishment-Based Renewal

这是一个基于成就的项目的更新，该项目旨在研究挥发性物质，如水和二氧化碳，如何在确定火山喷发的爆炸性方面发挥基础性作用。岩浆脱气的化学方面受到熔体中溶解挥发物和火山系统气体排放的研究的很好限制。最近的实验也提高了我们对富含挥发分的岩浆上升到地表时气泡的成核和生长方式的理解。然而，将挥发性相通过次火山系统的移动相关的化学和物理过程联系起来的研究仍然很少。在这次更新中，Cashman将通过以下方式解决这一问题：(1)扩展最近的工作，利用化学特征检查气体在火山系统中的物理运动；(2)开发新的技术来量化多孔火山岩的结构；(3)将多孔样品的结构与渗透性流动特性联系起来；以及(4)结合结构和化学数据，追踪挥发物(气体)在火山系统中的迁移。这项工作将提高我们对火山过程的基本理解和对火山监测数据的解释。具体的应用将是华盛顿州圣海伦斯火山的持续喷发。

This is an accomplishment-based renewal of a project designed to study how volatile species, such as H2O and CO2, can play a fundamental role in determining the explosivity of volcanic eruptions. Chemical aspects of magmatic degassing are well constrained from studies of dissolved volatiles in melts and gas emissions from volcanic systems. Recent experiments have also improved our understanding of the way the bubbles nucleate and grow as volatile-rich magma rises toward the surface. Still scarce, however, are studies that link chemical and physical processes related to the movement of volatile phases through subvolcanic systems. In this renewal, Cashman will address this problem by (1) extending recent work to examine physical movement of gases through volcanic systems using chemical signatures, (2) developing new techniques to quantify the structure of porous volcanic rocks, (3) relate the structure of porous samples to permeable flow characteristics, and (4) combine the structural and chemical data to trace the migration of volatiles (gases) through volcanic systems. This work will improve both our basic understanding of volcanic processes and our interpretation of volcano monitoring data. A specific application will be the ongoing eruption of Mount St. Helens, WA.