First mission: USGS UAS monitors gas emissions at Mount St. Helens

On September 25, 2018, a team of three scientists based at the USGS–Cascades Volcano Observatory conducted the first-ever USGS-led Unmanned Aircraft Systems (UAS) campaign at Mount St. Helens. The UAS survey was conducted with the permission and coordination of the U.S. Forest Service Mount St. Helens National Volcanic Monument.

The team used a multi-rotor UAS (“drone”) outfitted with a miniature USGS-developed MultiGAS sensor to measure quiescent gas emissions above the 2004-2008 lava dome within the crater of Mount St. Helens. These new technologies allowed the team to characterize degassing at Mount St. Helens in unprecedented detail.

The UAS survey confirmed that carbon dioxide (CO2) emissions from the 2004-2008 lava dome are extremely low and that water vapor constitutes the vast majority (>99%) of present-day gas emissions. Much of this water vapor is not derived from magma, but instead is produced when shallow meteoric and surface waters (e.g. snow melt) comes into contact with hot dome rocks, generating steam.

The UAS fills an important monitoring role at volcanoes. Its small size and maneuverability allow scientists to use portable monitoring technologies like the MultiGAS, in hazardous areas. The data is combined with that collected using traditional manned aircraft and at permanent monitoring stations, to gain a better understanding of gas emissions at Mount St. Helens. The successful application of these technologies at Mount St. Helens demonstrates the importance of these surveys in the Cascade Range and at other active volcanoes around the globe.