Explosive dome eruptions modulated by periodic gas-driven inflation

Geophysical Research Letters
By: , and 

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Abstract

Volcan Santiaguito (Guatemala) “breathes” with extraordinary regularity as the edifice's conduit system accumulates free gas, which periodically vents to the atmosphere. Periodic pressurization controls explosion timing, which nearly always occurs at peak inflation, as detected with tiltmeters. Tilt cycles in January 2012 reveal regular 26 ± 6 min inflation/deflation cycles corresponding to at least ~101 kg/s of gas fluxing the system. Very long period (VLP) earthquakes presage explosions and occur during cycles when inflation rates are most rapid. VLPs locate ~300 m below the vent and indicate mobilization of volatiles, which ascend at ~50 m/s. Rapid gas ascent feeds pyroclast-laden eruptions lasting several minutes and rising to ~1 km. VLPs are not observed during less rapid inflation episodes; instead, gas vents passively through the conduit producing no infrasound and no explosion. These observations intimate that steady gas exsolution and accumulation in shallow reservoirs may drive inflation cycles at open-vent silicic volcanoes.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Explosive dome eruptions modulated by periodic gas-driven inflation
Series title Geophysical Research Letters
DOI 10.1002/2014GL061310
Volume 41
Issue 16
Year Published 2014
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Science Center
Description 9 p.
First page 6689
Last page 6697