Local infrasound observations of large ash explosions at Augustine Volcano, Alaska, during January 11–28, 2006

Geophysical Research Letters
By: , and 

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Abstract

We present and interpret acoustic waveforms associated with a sequence of large explosion events that occurred during the initial stages of the 2006 eruption of Augustine Volcano, Alaska. During January 11–28, 2006, 13 large explosion events created ash-rich plumes that reached up to 14 km a.s.l., and generated atmospheric pressure waves that were recorded on scale by a microphone located at a distance of 3.2 km from the active vent. The variety of recorded waveforms included sharp N-shaped waves with durations of a few seconds, impulsive signals followed by complex codas, and extended signals with emergent character and durations up to minutes. Peak amplitudes varied between 14 and 105 Pa; inferred acoustic energies ranged between 2×108 and 4×109 J. A simple N-shaped short-duration signal recorded on January 11, 2006 was associated with the vent-opening blast that marked the beginning of the explosive eruption sequence. During the following days, waveforms with impulsive onsets and extended codas accompanied the eruptive activity, which was characterized by explosion events that generated large ash clouds and pyroclastic flows along the flanks of the volcano. Continuous acoustic waveforms that lacked a clear onset were more common during this period. On January 28, 2006, the occurrence of four large explosion events marked the end of this explosive eruption phase at Augustine Volcano. After a transitional period of about two days, characterized by many small discrete bursts, the eruption changed into a stage of more sustained and less explosive activity accompanied by the renewed growth of a summit lava dome.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Local infrasound observations of large ash explosions at Augustine Volcano, Alaska, during January 11–28, 2006
Series title Geophysical Research Letters
DOI 10.1029/2006GL026491
Volume 33
Issue 12
Year Published 2006
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Hazards Program
Description L12303; 5 p.
Country United States
State Alaska
Other Geospatial Augustine Volcano
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