Characterising the trigger mechanisms of volcanic eruptions

描述火山喷发的触发机制

• 批准号: 283274-2011
• 负责人: WilliamsJones, Glyn
• 金额: $ 1.6万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=525657
• 关键词: Characterising; trigger; mechanisms; volcanic; eruptions

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.

虽然在火山爆发的定量表征方面已经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仍然知之甚少。获得这方面的知识对于准确预测火山喷发至关重要，而这只有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才能实现。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变，并寻找其相关物理效应的表面证据。新鲜的、富含气体的岩浆侵入储层通常是喷发的触发因素，这种与积水岩浆相互作用的程度和速度将影响喷发的性质。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，并解释可能是喷发前兆的信号。虽然有一个协议，结晶和岩浆中挥发分的出溶作用对岩浆上升施加强有力的控制，这些过程发生的速度并不为人所知。几十年来，气相中CO2/SO2和HCl/SO2比值的时间变化一直被用来推断岩浆和热液系统的变化，对预测火山活动的变化很重要。然而，它只是与最近的进展，直接和间接的现场测量的火山气体成分和流量，更高精度的分析熔融包裹体成分，现在有可能准确地确定的浓度的主要前和后喷发的岩浆挥发物，从而量化火山脱气预算。然而，基本的问题仍然是关于在岩浆上升过程中的H2O，CO2，SO2，HCl和HF的演化，岩浆演化和脱气的作用，以及在表面上测量的火山排放的发散路径的影响。通过了解岩浆挥发物从源到汇的演变，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。