Characterising the trigger mechanisms of volcanic eruptions

尽管在火山喷发的定量表征方面取得了相当大的进展，但我们对控制火山活动的物理化学过程的了解仍然相对较少。获得这些知识对于准确预测火山喷发至关重要，而这只能通过整合多时间和多空间的地球化学、地球物理和遥感研究来实现。因此，我的研究计划的目标是了解岩浆挥发物从地幔到大气的演化过程，并寻找其相关物理效应的地表证据。新鲜的、富含气体的岩浆侵入储层往往是火山喷发的触发因素，这种岩浆与岩浆相互作用的程度和速度将影响火山喷发的性质。通过了解岩浆脱气现象，我们将能够更好地评估火山活动的演变，并解释可能是火山爆发前兆的信号。尽管人们一致认为，岩浆的结晶和挥发物的析出对岩浆上升起着强有力的控制作用，但这些过程发生的速度尚不清楚。几十年来，气相CO2/SO2和HCl/SO2比值的时间变化已被用于推断岩浆和热液系统的变化，并且在预测火山活动变化方面具有重要意义。然而，只有最近在火山气体组成和通量的直接和间接现场测量以及熔体包裹体组成的更高精度分析方面取得进展，现在才有可能准确地确定喷发前后主要岩浆挥发物的浓度，从而量化火山脱气预算。然而，关于岩浆上升过程中H2O、CO2、SO2、HCl和HF的演化，不同气相对岩浆演化和脱气的作用，以及不同路径对地表火山排放的影响等基本问题仍然存在。通过了解岩浆挥发物从源到汇的演化过程，这项研究有可能大大提高我们对火山系统如何从休眠发展到喷发的认识。

Although considerable progress has been made in the quantitative characterisation of volcanic eruptions, we still have relatively little knowledge of the physicochemical processes that control volcanic activity. Obtaining this knowledge is essential to the accurate prediction of eruptions, and this will only be achieved through the integration of multi-temporal and multi-spatial geochemical, geophysical and remote sensing studies. The objectives of my research program are thus to understand the evolution of magmatic volatiles from the mantle to the atmosphere and to seek surface evidence of their associated physical effects. The intrusion of fresh, gas-rich magma into a reservoir is often the trigger for an eruption, and the extent and rate of this interaction with the ponded magma will affect the nature of the eruption. By understanding the phenomenon of magma degassing, we will be better able to evaluate the evolution of volcanic activity and interpret signals that may be precursors to eruptions. Although there is agreement that crystallisation and the exsolution of volatiles from magmas exert a strong control on magma ascent, the rates at which these processes occur are not well known. Temporal variations in CO2/SO2 and HCl/SO2 ratios in the gas phase have been used for decades to infer changes in magmatic and hydrothermal systems, and are important in forecasting changes in volcanic activity. However, it is only with the recent advances in direct and indirect field measurements of volcanic gas compositions and fluxes, and higher precision analyses of melt inclusion compositions, that it is now possible to accurately determine the concentrations of the principal pre- and post-eruptive magmatic volatiles and thus quantify the volcano degassing budget. Nevertheless, fundamental questions remain regarding the evolution of H2O, CO2, SO2, HCl and HF during magma ascent, the role of separate gas phases on magma evolution and degassing, and the effects of divergent pathways on volcanic emissions measured on the surface. By understanding the evolution of magmatic volatiles from source to sink, this research has the potential to significantly advance our knowledge of how volcanic systems develop from dormancy through to eruption.