Seismic Imaging of Magmatic- and Subduction-Related Structures Beneath Arc Volcanoes: A Case Study at Mount Cleveland, Alaska

Date: 4/26/2019

Time: 02:00 PM

Room: Puget Sound

Cleveland Volcano is one of the most active volcanoes in the central-Aleutian island arc and represents one of the shallow-end members of depth to subducting slab at only ~ 65 km below the volcano. It was the site of a temporary deployment of twelve broadband seismometers from August 2015 – July 2016. We calculate P-to-s receiver functions using these as well as two permanent Alaska Volcano Observatory stations, which have operated since 2014, to determine new seismic constraints on the crustal structure beneath Cleveland Volcano and the depth to the subducting crust. At Cleveland Volcano we image a clear P-to-s conversion from the Moho discontinuity. However, its arrival time relative to the initial P-wave typically varies up to two seconds at a given station with later arrivals systematically corresponding to ray paths that have passed through crust directly beneath the volcano. The most likely explanation is that slow shear-wave velocities associated with the magmatic system beneath Cleveland Volcano contribute to the travel time variability, with perhaps a secondary contribution from smaller variations in Moho topography.

Presenting Author: Helen A. Janiszewski

Authors