Comparison of Crustal Magmatic Storage at Aleutian Volcanoes, Gareloi and Kanaga, using Teleseismic Receiver Function Analysis
Description:
The Aleutian arc is of considerable interest for geophysical and geologic investigations due to an abundance of 53 historically active volcanoes with several eruptions per year. Characterization of crustal magma storage depths and establishing ties to laterally variable subduction processes along the arc have been challenging due to the remote and harsh environment. In 2019, the Alaska Volcano Observatory conducted upgrades to the seismic network on Gareloi and Kanaga volcanoes in the Andreanof Islands. These upgrades increased the number of three-component broadband seismometers at these volcanoes to five and six, respectively. While these volcanoes are located only ~100 km from each other, there are key differences in observed seismic activity. Both have seismicity persistent through the upper- to mid-crust, but Gareloi’s rate of low-frequency seismicity is higher, and it is relatively devoid of volcano-tectonic earthquakes. To better understand what this might imply for crustal magma storage, we use the receiver function (RF) technique to provide independent constraints on subsurface magmatic system geometry.
We calculate RFs from teleseismic earthquakes with >M5.5 from 2019 to 2023. We use the P-to-S converted phases to constrain depths and velocities of abrupt boundaries in the crust related to magmatic structure. Both Gareloi and Kanaga provide good targets for this technique; each station produced on average ~419 RFs with overlapping ray path coverage between stations. We observe arrivals consistent with features in the mid-to-deep crust (~12–25 km depth) at both volcanoes. In addition, the RFs display complex patterns of back azimuthal variability that vary across stations at an individual volcano. We aim to interpret these complex arrivals and compare magma storage at the two volcanoes through forward modeling constraining crustal velocities.
Session: Structure and Behavior of the Alaska-Aleutian Subduction Zone [Poster Session]
Type: Poster
Date: 5/3/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Casey
Student Presenter: Yes
Invited Presentation:
Authors
Casey Wandasan Presenting Author Corresponding Author caseywan@hawaii.edu University of Hawaii at Manoa |
Helen Janiszewski hajanisz@hawaii.edu University of Hawaii at Manoa |
Ian Wynn iwynn@hawaii.edu University of Hawaii at Manoa |
John Power jpower@usgs.gov U.S. Geological Survey |
Matthew Haney mhaney@usgs.gov U.S. Geological Survey |
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Comparison of Crustal Magmatic Storage at Aleutian Volcanoes, Gareloi and Kanaga, using Teleseismic Receiver Function Analysis
Category
Structure and Behavior of the Alaska-Aleutian Subduction Zone