Helicopter magnetic and electromagnetic surveys at Mounts Adams, Baker and Rainier, Washington: implications for debris flow hazards and volcano hydrology

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Abstract

High‐resolution helicopter magnetic and electromagnetic (HEM) data flown over the rugged, ice‐covered Mt. Adams, Mt. Baker and Mt. Rainier volcanoes (Washington), reveal the distribution of alteration, water and ice thickness essential to evaluating volcanic landslide hazards. These data, combined with geological mapping and rock property measurements, indicate the presence of appreciable thicknesses (>500 m) of water‐saturated hydrothermally altered rock west of the modern summit of Mount Rainier in the Sunset Amphitheater region and in the central core of Mount Adams north of the summit. Alteration at Mount Baker is restricted to thinner (<300 m) zones beneath Sherman Crater and the Dorr Fumarole Fields. The EM data identified water‐saturated rocks from the surface to the detection limit (100–200 m) in discreet zones at Mt. Rainier and Mt Adams and over the entire summit region at Mt. Baker. The best estimates for ice thickness are obtained over relatively low resistivity (<800 ohm‐m) ground for the main ice cap on Mt. Adams and over most of the summit of Mt. Baker. The modeled distribution of alteration, pore fluids and partial ice volumes on the volcanoes helps identify likely sources for future alteration‐related debris flows, including the Sunset Amphitheater region at Mt. Rainier, steep cliffs at the western edge of the central altered zone at Mount Adams and eastern flanks of Mt. Baker.

Additional publication details

Publication type Conference Paper
Publication Subtype Conference Paper
Title Helicopter magnetic and electromagnetic surveys at Mounts Adams, Baker and Rainier, Washington: implications for debris flow hazards and volcano hydrology
DOI 10.1190/1.3659065
Year Published 2011
Language English
Publisher Society of Exploration Geophysicists
Contributing office(s) Crustal Geophysics and Geochemistry Science Center
Description 3 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title International Workshop on Gravity, Electrical & Magnetic Methods and Their Applications, Beijing, China, October 10-13, 2011
Conference Title International Workshop on Gravity, Electrical & Magnetic Methods and Their Applications, Beijing, China, October 10-13, 2011
Conference Location Beijing, China
Conference Date October 10-13, 2011
Online Only (Y/N) N
Additional Online Files (Y/N) N