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Date Permissions Signed

7-17-2017

Date of Award

Summer 2017

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Caplan-Auerbach, Jacqueline

Second Advisor

Stelling, Peter L.

Third Advisor

Foreman, Brady

Fourth Advisor

Dziak, Robert P.

Abstract

Landslides are an integral process in the development of submarine volcanoes, but these events are rarely recorded and observed. Therefore, understanding how the morphology of volcanoes evolve requires information on landslides. Hydroacoustic signals were analyzed for the purposes of characterizing frequent landslides on West Mata volcano during a 5-month eruptive period. Over 200 landslide signals have been compared in conjunction with hydroacoustic modeling to better understand the dynamics that control them. We used interference patterns produced by multipath rays to identify and model these slope failures. Landslides were most clearly captured on the north and west stations, suggesting a source on the western face of West Mata. This is consistent with a zone of high sediment accumulation previously found by bathymetric depth difference mapping. Landslides were found to initiate ~200-300 m below the summit and travel at speeds of 4-8 m/s, and possibly up to 20 m/s. Slope failures were observed during periods of high eruptive activity suggesting failure by unstable tephra loading preferentially at sites of previous sliding. Landslides at West Mata also tend to occur in clusters with decreasing run out distances over time. It is recommended that future studies involve a denser hydrophone network to better locate landslides and model slide mechanics.

Type

Text

Publisher

Western Washington University

OCLC Number

995175299

Digital Format

application/pdf

Geographic Coverage

South Pacific Ocean

Genre/Form

Academic thesis

Language

English

Rights

Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Included in

Geology Commons

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