Palma, José Luis; Calder, Eliza S.; Basualto, Daniel; Blake, Stephen and Rothery, David A.
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|DOI (Digital Object Identifier) Link:||http://doi.org/10.1029/2008JB005577|
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The characteristics of the open vent activity of Villarrica volcano, Chile, were studied in detail by integrating visual observations of the lava lake, analysis of the seismic tremor, and measurements of SO2 flux. The outgassing activity comprises a persistent gas plume emission from the bottom of the crater as well as frequent explosive events. Three main styles of bubble bursting were identified at the surface of the active lava lake: seething magma, small short-lived lava fountains, and Strombolian explosions. Seething magma consists of continual burst of relatively small bubbles (a few meters in diameter) with varying strength over the entire surface of the lava lake. Small lava fountains, seen as a vigorous extension of seething magma, commonly have durations of 20–120 s and reach 10–40 m high above the lava lake. Correlations between seismicity and visual observations indicate that the seismic tremor is mostly caused by the explosive outgassing activity. Furthermore, for different periods between 2000 and 2006, during which the activity remained comparable, the real-time seismic amplitude measurement system (RSAM) and SO2 emission rates show a very good correlation. Higher SO2 emissions appeared to be related to higher levels of the lava lake, stronger bubble bursting activity, and changes in the morphology and texture of the crater floor. Background (low) levels of activity correspond to a lava lake located >80 m below the crater rim, small and/or blocky morphology of the roof, seismic amplitude (RSAM) lower than 25 units, few volcano-tectonic earthquakes, and daily averages of SO2 emissions lower than 600 Mg/d.
|Item Type:||Journal Article|
|Extra Information:||An edited version of this paper was published by AGU. Copyright 2009 American Geophysical Union
|Academic Unit/Department:||Science > Environment, Earth and Ecosystems
Science > Physical Sciences
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)|
|Depositing User:||David Rothery|
|Date Deposited:||19 Jan 2009 06:38|
|Last Modified:||24 Feb 2016 06:13|
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