A multi-component gas analyzer system (Multi-GAS) is an instrument package used to take real-time high-resolution measurements of volcanic gases.
[2][3] The system can be used for individual surveys or set up as permanent stations[1] connected to radio transmitters for transmission of data from remote locations.
[6] The development of this instrument has helped scientists to monitor real-time changes in volcanic gas composition, allowing for more rapid hazard mitigation and an enhanced understanding of volcano processes.
[9] The instruments are packaged in compact, portable, weather-resistant containers allowing for in situ measurements of various types of outgassing terrains.
Multi-GAS measurements of real-time CO2/SO2 ratios can allow detection of the pre-eruptive degassing of rising magmas, improving the prediction of volcanic activity.
[1] As magma rises beneath the surface CO2 solubility decreases and the gas readily exsolves, leading to an increase in the CO2/SO2 ratio.
In the Americas, Villarrica,[22] Masaya Volcano,[23] Mount St. Helens,[17] and Soufrière Hills[24] are also observed with instruments for changes in volcanic gas output.
Degassing activity increases after ground movement due to the opening of new paths (e.g. fractures) in the crust for the gas to flow.