TELESEISMIC P AND S WAVE ATTENUATION CONSTRAINTS ON TEMPERATURE AND MELT OF THE UPPER MANTLE IN THE ALASKA SUBDUCTION ZONE

• Main Author: Soto Castaneda, Roque Alberto
• Other Authors: Abers, Geoffrey, Keranen, Kathleen
• Format: Thesis
• Language: English
• Published: 2020
• Subjects: Alaska; Attenuation; Mantle; Seismology; Subduction; Temperature; Pacific; alaska range; Yakutat
• Online Access: https://hdl.handle.net/1813/70311; http://dissertations.umi.com/cornell:10887; https://doi.org/10.7298/v15p-e163

112 pages Supplemental file(s) description: Data Spreadsheet. Recent broadband deployments in Alaska provide an excellent opportunity to advance our understanding of the Alaska-Aleutians subduction system, with implications for subduction processes worldwide. Seismic attenuation, measured from teleseismic body waves, provides a strong constraint on thermal structure. We measure P and S wave attenuation from pairwise amplitude and phase spectral ratios for teleseisms recorded at 204 stations including the WVLF (Wrangell Volcanics & subducting Lithosphere Fate) array. This study applies a novel method for measuring teleseismic attenuation by Eilon and Abers (2017) to subduction zones for the first time and the results are encouraging. Low attenuation across both the WVF and east of the Alaska Range suggest Yakutat subduction beneath the WVF and Pacific/Yakutat subduction extending past the east edge of the Alaskan-Aleutians Wadati-Benioff zone. Comparison with previous Alaska attenuation studies shows slightly higher attenuation, which are likely due to a difference in paths sampled.