115-5 Comparative analysis of VSWIR reflectance data and hand collected measurements of Great Sitkin’s ongoing eruption.

Session: Petrology, Volcanology, and Mantle Plumes across the Solar System (Posters)

Presenting Author:

Authors:

Abstract:

Great Sitkin is a remote stratovolcano located in the Aleutian Islands off the coast of Alaska. Its current eruption period started in May of 2021 and is still ongoing; a lava dome grew in a preexisting summit crater that also contained most of the new lava. However there have been a few flows that have spilled over the sides of the crater to the north, northwest, east, and south. Samples were collected by the Alaska Volcano Observatory (AVO) from the active eastern flow in September of 2023. Being able to identify minerals and the bulk composition is important for understanding the potential hazards associated with dome growth on stratovolcanoes. Dome collapses and edifice failures can be attributed to the weakening of volcanic material; both glass and hydrothermal alteration can produce clay, allowing for instability that could result in a hazard.

The remote nature of Great Sitkin provides an opportunity to utilize remote sensed data to monitor volcanic activity; the visible near infrared and shortwave infrared (VSWIR) portion of the electromagnetic spectrum (350-2500nm) is useful for mineral identification, bulk composition, and the effects of a materials structure. The visible near infrared portion is sensitive to iron content while the shortwave infrared portion is strong at identifying clay minerals often associated with hydrothermal alteration. This makes it a good candidate for studying the progression of Great Sitkin's eruption activity over the last three years. However, due to the spatial resolution of satellite data there is also a need to understand how the imagery compares to data collected on hand samples. By using satellite data over the different phases of its eruption and data collected from a portable spectrometer on hand samples, this allows for the exploration of how the two can be used together to study hazards associated with dome growth on remote volcanoes.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8092

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