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What Has Unimak Island in Alaska Witnessed in the Last ~30 Years? – a Seismic Recap

Description: 

Seismic swarms on volcanoes along a subduction arc could be reflective of a multitude of geophysical processes. These processes can broadly be volcanic, tectonic, or cryospheric in origin, or a combination of these. Unimak Island that exhibits subduction arc volcanism is located in the central part of the Alaska-Aleutian subduction zone where the Pacific plate subducts beneath the North-American plate, normal to the trench-line with low coupling between the plates. The island hosts several volcanoes such as Roundtop, Isanotski, Shishaldin, Fisher, and Westdahl. Of these, Westdahl, Fisher, and Shishaldin, are considered active due to historic volcanism, volcano seismicity, and deformation cycles. In this study, Unimak Island is divided into smaller regions based on the locations of the three active volcanoes and their seismic activity from 1990-2023, including the recent 2023 unrest at Shishaldin. The seismicity in these regions is categorized into multiple time windows depending on the length of activity and quiescence. The seismicity in each spatio-temporal unit is used to (1) characterize individual swarm clusters, (2) identify correlations with specific periods of volcanic unrest defined by different observations (eruptions, deformation etc.), and (3) identify signatures of possible interactions between the three volcanoes. The study uses relocated seismicity (Klein, 2002) from the Alaska Volcano Observatory (AVO) seismic catalog (available through USGS), and eruption history and geodetic observations curated by AVO.

Session: Advances in Operational and Research Analysis of Earthquake Swarms [Poster Session]

Type: Poster

Date: 5/3/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Revathy

Student Presenter: No

Invited Presentation: 

Authors