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Time-evolving surface and subsurface signatures of Quaternary volcanism in the Cascades arc

July 13, 2020

Increased resolution of data constraining topography and crustal structures provides new quantitative ways to assess province-scale surface-subsurface connections beneath volcanoes. We used a database of mapped vents to extract edifices with known epoch ages from digital elevation models (DEMs) in the Cascades arc (western North America), deriving volumes that likely represent ∼50% of total Quaternary eruptive output. Edifice volumes and spatial vent density correlate with diverse geophysical data that fingerprint magmatic influence in the upper crust. Variations in subsurface structures consistent with volcanism are common beneath Quaternary vents throughout the arc, but they are more strongly associated with younger vents. Geophysical magmatic signatures increase in the central and southern Cascade Range (Cascades), where eruptive output is largest and vents are closely spaced. Vents and correlated crustal structures, as well as temporal transitions in the degree of spatially localized versus distributed eruptions, define centers with lateral extents of ∼100 km throughout the arc, suggesting a time-evolving spatial focusing of magma ascent.

Publication Year 2020
Title Time-evolving surface and subsurface signatures of Quaternary volcanism in the Cascades arc
DOI 10.1130/G47706.1
Authors Daniel O'Hara, Leif Karlstrom, David W. Ramsey
Publication Type Article
Publication Subtype Journal Article
Series Title Geology
Index ID 70222537
Record Source USGS Publications Warehouse
USGS Organization Volcano Science Center