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Date of Award

Spring 2025

Document Type

Masters Thesis

Department or Program Affiliation

Geology

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Caplan-Auerbach, Jacqueline

Second Advisor

Boujibar, Asmaa

Third Advisor

Walowski, Kristina

Fourth Advisor

Soule, S. Adam, 1975-

Abstract

When lava meets seawater, it can fragment or remain as an intact lava flow extending up to hundreds of meters offshore. At ocean island volcanoes, these different lava emplacements can impact the stability of the submarine flank, as fragmental material is more likely to exhibit mass wasting. Previous studies suggest that the manner of lava emplacement may be controlled by the effusion rate (m3/s) or the type of lava: ʻaʻā or pāhoehoe. Two recent eruptions of Kīlauea volcano in Hawaiʻi had two vastly different effusion rates which may have affected the mechanisms of lava emplacement. In this study we utilize hydroacoustic observations, images, and descriptions of the Puʻuʻōʻō eruption (1983-2018) and the Ahuʻailāʻau eruption (2018) to explore how lava was emplaced on the submarine south flank (SSF). Ocean bottom seismometers equipped with hydrophones (OBS/H) recorded the sounds of lava-water interactions (LWI) occurring offshore during three time periods: January-April 1998, September 2010-May 2011 and July-September 2018. All three data sets show discrete signals associated with LWI and we hypothesize that prolonged low-frequency signals are associated with diverse types of lava flows, as the frequency and durations of these signal varied per eruption. Only the 1998 and 2010-2011 data show signals identified as submarine landslides, some of which are associated with observed collapses of the coastal lava delta. No collapses of the coastal delta were observed in 2018, and remotely operated vehicle (ROV) observations showed intact flows < 2 km offshore — our hydroacoustic data provide further evidence of these behaviors. Waveform analyses including cross-correlation of LWI signals were completed to investigate the patterns in the waveforms and reflection timing — as these provide evidence on the mechanisms and locations of the sounds, respectively. Differentiating these emplacement mechanisms during the two eruptions provides insight into the growth and stability of the SSF.

Type

Text

Keywords

hydroacoustic, lava, Kilauea, eruption, lava-water interactions, LWI, Hawai'i, volcano, collapse, flank

Publisher

Western Washington University

OCLC Number

1522762975

Subject – LCSH

Lava--Hawaii--Kilauea Volcano; Lava flows--Hawaii--Kilauea Volcano; Underwater acoustics--Hawaii--Kilauea Volcano; Landslides--Hawaii--Kilauea Volcano--Analysis; Kilauea Volcano (Hawaii)--Eruption, 1983-2018, Kilauea Volcano (Hawaii)--Eruption, 2018

Geographic Coverage

Kilauea Volcano (Hawaii)

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

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

Rights Statement

http://rightsstatements.org/vocab/NKC/1.0/

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