Linking magma storage and ascent to eruption volume and composition at an arc caldera

Geophysical Research Letters
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Abstract

Conceptual models of magma storage and transport under calderas favor a connected system of sills and dikes. These features are individually below the resolution of standard seismic tomography, but radial seismic anisotropy can reveal where they exist in aggregate. We model radial anisotropy at Okmok caldera, Alaska, to demonstrate the presence of a caldera-centered stacked sill complex and surrounding dike system. We show that ascending magma, inferred from seismicity, either intersects the sill complex, resulting in a larger volume eruption of evolved magma, or bypasses the overlying sill complex via dikes, resulting in a low-volume mafic eruption. Our results exemplify how the locations of magma storage and paths of transport impact eruption size and composition. As this type of crustal storage is likely common to many calderas, this analysis offers a potential new framework for volcano observatories to forecast the size of impending eruptions.

Suggested Citation

Miller, D., Bennington, N., Haney, M.M., Bedrosian, P.A., Key, K., Thurber, C., Hart, L., and Ohlendorf, S., 2020, Linking magma storage and ascent to eruption volume and composition at an arc caldera: Geophysical Research Letters, v. 47, no. 14, e2020GL088122, 9 p., https://doi.org/10.1029/2020GL088122.

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Publication type Article
Publication Subtype Journal Article
Title Linking magma storage and ascent to eruption volume and composition at an arc caldera
Series title Geophysical Research Letters
DOI 10.1029/2020GL088122
Volume 47
Issue 14
Publication Date July 14, 2020
Year Published 2020
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Science Center
Description e2020GL088122, 9 p.
Country United States
State Alaska
Other Geospatial Aleutian Islands, Okmok caldera
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