The prevalence and significance of offset magma reservoirs at arc volcanoes

Geophysical Research Letters
By: , and 



Determining the spatial relations between volcanic edifices and their underlying magma storage zones is fundamental for characterizing long-term evolution and short-term unrest. We compile centroid locations of upper crustal magma reservoirs at 56 arc volcanoes inferred from seismic, magnetotelluric, and geodetic studies. We show that magma reservoirs are often horizontally offset from their associated volcanic edifices by multiple kilometers, and the degree of offset broadly scales with reservoir depth. Approximately 20% of inferred magma reservoir centroids occur outside of the overlying volcano’s mean radius. Furthermore, reservoir offset is inversely correlated with edifice size. Taking edifice volume as a proxy for long-term magmatic flux, we suggest that high flux or prolonged magmatism leads to more centralized magma storage beneath arc volcanoes by overprinting upper crustal heterogeneities that would otherwise affect magma ascent. Edifice volumes therefore reflect the spatial distribution of underlying magma storage, which could help guide monitoring strategies at volcanoes
Publication type Article
Publication Subtype Journal Article
Title The prevalence and significance of offset magma reservoirs at arc volcanoes
Series title Geophysical Research Letters
DOI 10.1029/2020GL087856
Volume 47
Issue 14
Year Published 2020
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Science Center
Description e2020GL087856, 10 p.
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