Session: Observations of Volcanism in the Three Spheres: Land, Air and Sea [Poster]
Type: Poster
Date: 4/26/2019
Time: 06:00 PM
Room: Fifth Avenue
[Withdrawn] Insights Into Shallow Submarine Explosion Dynamics at Bogoslof Volcano From Infrasound, Hydroacoustic and Seismic Data
Shallow submarine volcanoes pose unique scientific and monitoring challenges. The interaction between water and magma creates violent explosions just below the surface, but the inaccessibility of submerged volcanoes means they are typically not instrumented. This both increases the risk to marine and aviation traffic and leaves the underlying eruption physics poorly understood. The 2016-2017 submarine eruption of Bogoslof volcano, Alaska, is a unique example of a shallow submarine eruption that produced more than 70 explosive events over 9 months, many of which were captured on infrasound, seismic, and hydroacoustic stations. The nearest infrasonic and seismic monitoring stations are on islands more than 50 km from Bogoslof, making detection and characterization of eruptive events challenging. A campaign hydrophone was installed in May of 2017 near the volcano and captured the second half of the eruption sequence. The eruption infrasound is dominated by low frequency energy, and modeling of discrete low frequency signals associated with many of the explosions indicate large magmatic gas bubbles expanding at the water-air interface were responsible for generating these signals. Seismic signals recorded during unrest on nearby islands showed varying T phase amplitudes, which are used as a proxy for source depth. The single hydrophone recorded a wide variety of events, including high-amplitude signals during explosions. Some of the strongest explosions produced clear signals on all three sensors. Travel-time corrected onsets for some of the strongest explosions show a surprising result: infrasound signals arrive first, followed by hydroacoustic and then seismic. These data support the development of a new, top-down explosion model in cases where gas-rich magmas are erupted from shallow submarine vents.
Presenting Author: John J. Lyons
Additional Authors
John J Lyons jlyons@usgs.gov U.S. Geological Survey, Anchorage, Alaska, United States Presenting Author
Corresponding Author
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Aaron Wech awech@usgs.gov U.S. Geological Survey, Anchorage, Alaska, United States |
Gabrielle Tepp gtepp@usgs.gov U.S. Geological Survey, Anchorage, Alaska, United States |
Matthew Haney mhaney@usgs.gov U.S. Geological Survey, Anchorage, Alaska, United States |
David Fee dfee1@alaska.edu Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska, United States |
Chris Waythomas cwaythomas@usgs.gov U.S. Geological Survey, Alaska Volcano Observatory, Anchorage, Alaska, United States |
[Withdrawn] Insights Into Shallow Submarine Explosion Dynamics at Bogoslof Volcano From Infrasound, Hydroacoustic and Seismic Data
Category
Observations of Volcanism in the Three Spheres: Land, Air and Sea