Multi-component gas analyzer system
A multi-component gas analyzer system (Multi-GAS) is an instrument package used to take real-time high-resolution measurements of volcanic gases. A Multi-GAS package includes an infrared spectrometer for CO2, two electrochemical sensors for SO2 and H2S, and pressure–temperature–humidity sensors, all in a weatherproof box. The system can be used for individual surveys or set up as permanent stations connected to radio transmitters for transmission of data from remote locations. The instrument package is portable, and its operation and data analysis are simple enough to be conducted by non-specialists. Multi-GAS instruments have been used to measure volcanic gases at Mount Etna, Stromboli, Vulcano Italy, Villarrica (volcano) Chile, Masaya Volcano Nicaragua, Mount Yasur, Miyake-jima and Mount Asama Japan, Soufrière Hills Montserrat, with permanent installations at Etna and Stromboli. 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. Multi-component gas analyzer systems are used for measuring the major components of volcanic gases. CO2, SO2, H2S, and pressure-temperature-humidity sensors are typically included in a package. Other electrochemical sensors have been successfully incorporated as well, including for H2 and HCl. The instruments are packaged in compact, portable, weather-resistant containers allowing for in situ measurements of various types of outgassing terrains. Gas is pumped into the system at a constant flow rate through a silicone tube placed near the location of interest. A data-logger is used to automatically record and convert the voltage values from the sensors into gas composition values. While the field use of a multi-GAS is simple, postprocessing of the data can be complex. This is due to factors like instrument drift, and atmospheric or environmental conditions. The system can be used for short term or long term studies.
