Analysing hidden messages in high temperature fumarolic emissions

Abstract

Fumarolic emissions from active volcanoes are typically comprised of gases that are not long removed from their parental magmas. As such, they carry a wealth of information about the nature of those melt(s), but also about the journey the vapours have had en route to the surface. Although we have been studying volcanic volatile emission chemistries in campaign fashion for over 40 years in New Zealand, we actually have little idea of what influences their behaviour over short time scales, the intricacies of the interactions between magmatic volatile streams and their enclosing hydrothermal system(s), or the ways in which the gas streams respond to periods of volcanic unrest. In this study, we take a 3-pronged approach to characterising fumarole behaviour. First, we develop a real time, autonomous data station for deployment onto the highest temperature fumarole on the main crater floor of White Island (so-called Fumarole 0) which will record and telemeter key physical and chemical parameters back to the mainland in near-real time. Secondly, we conduct a first ever resistive tomographic survey of the subsurface conduit to ascertain the nature of the interaction between the fumarolic gases and the enclosing hydrothermal fluids; and 3) we develop a numerical model of fumarolic environments with which we can test the impacts of varying key parameters.