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Gas emissions from Mount Cleveland, Alaska, provide insights into volcanic processes

Christoph Kern 1, Skye Kushner2, Ellie Boyce3, Vanesa Burgos3, Max Kaufman3, Allan Lerner1, Taryn Lopez3, John Power4, Claire Puleio3, Diana Roman5, Valerie Wasser3, Cynthia Werner6, Conor Bacon7

  • Affiliations: 1U.S. Geological Survey Cascades Volcano Observatory, Vancouver, USA; 2University of Alaska Anchorage, Anchorage, USA; 3University of Alaska Fairbanks, Fairbanks, USA; 4U.S. Geological Survey Alaska Volcano Observatory, Anchorage, USA; 5Carnegie Institution for Science, Washington DC, USA; 6U.S. Geological Survey Contractor, New Plymouth, NZ; 7Lamont Doherty Earth Observatory, Columbia University, New York, USA

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 275

  • Programme No: 3.17.40

  • Theme 3 > Session 17

Abstract

Mount Cleveland is an andesitic stratovolcano located in the remote Aleutian Islands approximately 1,500 km west of Anchorage, Alaska, and is one of the most active volcanoes in the United States. Since 2005, activity at Mount Cleveland has been characterized by dome growth within the volcano's summit crater, intermittent explosive dome destruction events, and persistent gas and thermal emissions. The volcano is considered an open system, and explosions commonly occur without seismic precursors. In 2022 and 2023, two permanent scanning differential optical absorption spectrometers (scanning DOAS) were installed on the east side of the volcanic edifice and since then allow semi-continuous tracking of Mount Cleveland's sulfur dioxide (SO2) emissions, even when emission rates are below those detectable from spaceborne instruments, as is commonly the case. The measurements show that SO2 emission rates are typically in the range of 200 -- 500 metric tons per day (t/d) but bursts of up to several thousand t/d occur intermittently, possibly associated with gas slugs rising from depth or small Vulcanian explosions. The spectroscopic DOAS data also show that halogen oxides, especially bromine monoxide (BrO), is present in the gas plumes at times. BrO is formed when hydrogen bromide is emitted from volcanic vents at temperatures above about 1000 K and only when gases do not significantly interact with water on their way to the atmosphere. In this contribution, we explore possible connections between gas emission rates, plume chemical speciation, and other observable volcanic processes at Mount Cleveland.