Projecting Air Quality Impacts for the Next Eruption of Mauna Loa Volcano, Hawai‘i

Recent and ongoing summit inflation and elevated seismicity at Mauna Loa volcano, signal increased restlessness for this active volcano. Mauna Loa (elevation 4,169 m) has erupted 33 times since its first well-documented historical eruption in 1843. For about the past 1000 years, eruptions have predominantly occurred from vents located in the summit area and on the volcano’s NE and SW rift zones. The recent increase in volcano deformation and seismic activity may be interpreted as magma accumulating in the volcano's shallow reservoir. Currently, degassing in the Sulfur Cone area high on the SW rift zone includes elevated levels of H₂S, however, the onset of an eruption would lead to significant SO₂ degassing.

The gas-emission impacts of several eruption scenarios are simulated with the University of Hawai‘i's VMAP (Vog Measurement and Prediction) model to determine the range of potential impacts on local (island scale), regional (state of Hawaii), and global scales (pan-Pacific). Local impacts from future gas emissions are important for Hawaii County Civil Defense and the Hawaii Emergency Management Agency to anticipate the potential severity of impacts from future eruptions of Mauna Loa. Global and regional air quality impacts are also possible due to the large gas emissions associated with voluminous flows erupted from Mauna Loa, as well as the potential for volcanic gases to be emitted/discharged at high altitude.

The scenarios use eruption parameters based on 20th century eruptive events at the summit and the rift zones. SO₂ is the primary gas simulated, with active conversion to SO₄. Results are presented for gas and particle surface concentrations around the Island of Hawai‘i, and around the Pacific Basin. The significance of vent elevation relative to the trade wind inversion layer will be addressed as it relates to local, regional, and global impacts.