气候变化领域集成服务门户(CCPortal): Airborne Geophysical Imaging of Weak Zones on Iliamna Volcano, Alaska: Implications for Slope Stability

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DOI	10.1029/2020JB020807
	Airborne Geophysical Imaging of Weak Zones on Iliamna Volcano, Alaska: Implications for Slope Stability
	Peterson D.E.; Finn C.A.; Bedrosian P.A.
发表日期	2021
ISSN	21699313
卷号	126 期号:3
英文摘要	Water-saturated, hydrothermally altered rocks reduce the strength of volcanic edifices and increase the potential for sector collapses and far-traveled mass flows of unconsolidated debris. Iliamna Volcano is an andesitic stratovolcano located on the western side of the Cook Inlet, ∼225 km southwest of Anchorage and is a source of repeated avalanches. The widespread snow and ice cover on Iliamna Volcano make surface alteration difficult to identify. However, intense hydrothermal alteration significantly reduces both the electrical resistivity and magnetization of volcanic rock and can therefore be identified with airborne geophysical measurements. We use airborne electromagnetic and magnetic data to map snow and ice thickness and identify underlying alteration zones at Iliamna Volcano, Alaska. Resistivities were calculated to an average depth of >300 m, and a 3-D susceptibility model extends from the surface to the base of the volcano, about 3,000 m below the summit. Geophysical models image low resistivity (<30 ohm-m) and low susceptibilities near the summit of Iliamna and below its older vent complex, with the low susceptibilities indicating alteration up to ∼800 m in thickness. Thin conductors (∼50–100 m thick) on the edifice slopes coincide with recorded locations of repeated debris avalanches over the past ∼60 years and are attributed to saturated zones at high elevation. Three-dimensional slope stability models based upon the geophysically constrained alteration distribution suggest the edifice of Iliamna is unstable and could lead to collapse scars ∼400 m deep near the current and former vent complexes. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.
英文关键词	airborne geophysics; electromagnetics; Iliamna; landslides; magnetics; volcanology
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187293
作者单位	U.S. Geological Survey, Geology, Geophysics, Geochemistry Science Center, Denver, CO, United States
推荐引用方式 GB/T 7714	Peterson D.E.,Finn C.A.,Bedrosian P.A.. Airborne Geophysical Imaging of Weak Zones on Iliamna Volcano, Alaska: Implications for Slope Stability[J],2021,126(3).
APA	Peterson D.E.,Finn C.A.,&Bedrosian P.A..(2021).Airborne Geophysical Imaging of Weak Zones on Iliamna Volcano, Alaska: Implications for Slope Stability.Journal of Geophysical Research: Solid Earth,126(3).
MLA	Peterson D.E.,et al."Airborne Geophysical Imaging of Weak Zones on Iliamna Volcano, Alaska: Implications for Slope Stability".Journal of Geophysical Research: Solid Earth 126.3(2021).