Integrated real-time observations with stratigraphically-constrained samples of the 2018 eruption of Veniaminof, Alaska
Abstract
Open-system volcanoes can erupt with little precursory deformation or seismicity and challenge efforts to forecast new eruptions. The September-December 2018 eruption of Veniaminof volcano, Alaska started with abrupt onset of harmonic tremor two days prior to the first confirmed minor ash emissions in satellite and web camera images. The eruption proceeded for almost four months, emitting minor tephras in primarily strombolian activity and effusing many short (<2 km) lava flows from the same vent that erupted basaltic andesites in 1983, 1993, 2002-2009, and 2013. Lavas built up a 0.8 km2 flow field entrenched against caldera-filling ice. The largest ash -producing event was on November 21, yielding a plume that extended >400 km from the volcano that prompted the Alaska Volcano Observatory (AVO) to raise the aviation alert color code to RED. This event was the most significant ash event recorded historically at Veniaminof.
Optical and thermal satellite observations document a detailed sequence of explosive events, lava flow field growth, and effusion rate changes despite the volcano's remote location. In July 2019, we were able to sample lavas and tephra deposited in nearby snow from this eruption sequence. These appear to be basaltic andesites similar to those from prior eruptions of the historically active cone. Remote sensing observations of the eruption allow us to assign the sampled deposits to specific events during the eruption sequence. The textural and petrologic changes in the stratigraphically sampled tephras through the eruption sequence, including bubble and microlite number densities, glass composition, componentry, and mineral zoning, will improve understanding of the magmatic lead-up to the eruption and the syn-eruption evolution that produced energetic explosive events. These results can illustrate how rapid sampling of eruption products can help inform response to an ongoing eruption, and petrologic data will shed light on the magmatic evolution of an open-system volcanic eruption. In addition, we demonstrate a way that observatory staff and academic partners can work together to best analyze eruption products and complement individual efforts.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.V23I0306L
- Keywords:
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- 3275 Uncertainty quantification;
- MATHEMATICAL GEOPHYSICS;
- 8419 Volcano monitoring;
- VOLCANOLOGY;
- 8488 Volcanic hazards and risks;
- VOLCANOLOGY;
- 8494 Instruments and techniques;
- VOLCANOLOGY