Continuous Volcano Monitoring Using a Field-Portable Helium Isotope Detector Active
The injection of magma into subvolcanic magma reservoirs is one of the most significant triggers of volcanic eruptions. It is often manifested by an increase in CO2 emissions and in the helium isotopic ratio (3He/4He) measured in discharged gases. Temporal variations of helium isotope ratios in volcanic gases preceded eruptions at Ontake Volcano in Japan (September 2014) and at Etna Volcano in Italy. However, temporal correlations in these examples were demonstrated only post-eruption because real-time continuous gas data was lacking. The USGS National Innovation Center and Volcano Hazards Program co-funded a collaboration with the University of Hawaii to develop a new field-portable instrument to measure in-situ helium isotopic ratios in volcanic gases. This new instrument, with two compact mass spectrometers, an ion trap and a frequency-modified quadrupole mass spectrometer can measure six helium isotope ratio values per day.
Compact mass spectrometers (MSs) can provide simultaneous multispecies analysis with high sensitivity and precision. For volcanic gas monitoring in situ, instrumental mass spectrometry requires reliability and ruggedness combined with low power usage and portability. The Volcanic Gas Analytical Monitor (VGAM) is capable of quantitative molecular analysis of a variety of atmospheric and volcanic gases in a single sensor by ion trap mass spectrometry.
Portable helium gas analyzer for volcanic monitoring
The injection of magma into subvolcanic magma reservoirs is one of the most significant triggers of volcanic eruptions. It is often manifested by an increase in CO2 emissions and in the helium isotopic ratio (3He/4He) measured in discharged gases. Temporal variations of helium isotope ratios in volcanic gases preceded eruptions at Ontake Volcano in Japan (September 2014) and at Etna Volcano in Italy. However, temporal correlations in these examples were demonstrated only post-eruption because real-time continuous gas data was lacking. The USGS National Innovation Center and Volcano Hazards Program co-funded a collaboration with the University of Hawaii to develop a new field-portable instrument to measure in-situ helium isotopic ratios in volcanic gases. This new instrument, with two compact mass spectrometers, an ion trap and a frequency-modified quadrupole mass spectrometer can measure six helium isotope ratio values per day. In the summer of 2018, the new helium isotope instrument was deployed for four months near Horseshoe Lake, on the flanks of Mammoth Mountain volcano in eastern California. This volcano is characterized by high CO2 emissions that have varied along with helium isotopic compositions during periods of volcanic unrest. In December 2020, the instrument was deployed for two weeks at Kilauea Volcano, Hawaii and measured changes in the isotopic values that preceded an eruption. It is envisioned that further enhancements and successful development and demonstration of such instruments will enable them to be incorporated into monitoring networks at volcanoes worldwide.
The injection of magma into subvolcanic magma reservoirs is one of the most significant triggers of volcanic eruptions. It is often manifested by an increase in CO2 emissions and in the helium isotopic ratio (3He/4He) measured in discharged gases. Temporal variations of helium isotope ratios in volcanic gases preceded eruptions at Ontake Volcano in Japan (September 2014) and at Etna Volcano in Italy. However, temporal correlations in these examples were demonstrated only post-eruption because real-time continuous gas data was lacking. The USGS National Innovation Center and Volcano Hazards Program co-funded a collaboration with the University of Hawaii to develop a new field-portable instrument to measure in-situ helium isotopic ratios in volcanic gases. This new instrument, with two compact mass spectrometers, an ion trap and a frequency-modified quadrupole mass spectrometer can measure six helium isotope ratio values per day.
Compact mass spectrometers (MSs) can provide simultaneous multispecies analysis with high sensitivity and precision. For volcanic gas monitoring in situ, instrumental mass spectrometry requires reliability and ruggedness combined with low power usage and portability. The Volcanic Gas Analytical Monitor (VGAM) is capable of quantitative molecular analysis of a variety of atmospheric and volcanic gases in a single sensor by ion trap mass spectrometry.
Portable helium gas analyzer for volcanic monitoring
The injection of magma into subvolcanic magma reservoirs is one of the most significant triggers of volcanic eruptions. It is often manifested by an increase in CO2 emissions and in the helium isotopic ratio (3He/4He) measured in discharged gases. Temporal variations of helium isotope ratios in volcanic gases preceded eruptions at Ontake Volcano in Japan (September 2014) and at Etna Volcano in Italy. However, temporal correlations in these examples were demonstrated only post-eruption because real-time continuous gas data was lacking. The USGS National Innovation Center and Volcano Hazards Program co-funded a collaboration with the University of Hawaii to develop a new field-portable instrument to measure in-situ helium isotopic ratios in volcanic gases. This new instrument, with two compact mass spectrometers, an ion trap and a frequency-modified quadrupole mass spectrometer can measure six helium isotope ratio values per day. In the summer of 2018, the new helium isotope instrument was deployed for four months near Horseshoe Lake, on the flanks of Mammoth Mountain volcano in eastern California. This volcano is characterized by high CO2 emissions that have varied along with helium isotopic compositions during periods of volcanic unrest. In December 2020, the instrument was deployed for two weeks at Kilauea Volcano, Hawaii and measured changes in the isotopic values that preceded an eruption. It is envisioned that further enhancements and successful development and demonstration of such instruments will enable them to be incorporated into monitoring networks at volcanoes worldwide.