Remote measurement of volcanic gases by Fourier transform infrared spectroscopy

Volcanic gases are 'telegrams from the Earth's interior', carrying information on conditions in deep magmatic sources, and fluid-rock interaction at higher levels in the crust. They are also the ultimate source of the Earth's secondary atmosphere. Fourier transform infrared (FTIR) spectroscopy has only recently been applied to volcanological field studies but it offers remarkable potential as a means for rapid, remote surveillance of a wide range of volcanic gases. Gas geochemistry is not only beneficial in volcanic hazards assessment but is also crucial to understanding the chemical equilibria in rising magma bodies as well as the contribution and consequences of volcanic degassing to the atmosphere. This paper reviews the application of FTIR spectroscopy tcs volcanological studies, and considers some of the challenges that must be met if the technique is to be fully embraced by the volcanic hazards community. The compilation of volcanic gas data obtained by field spectroscopy presented here can assist in design of future gas measurement campaigns by FTIR or related spectroscopic techniques.