volcano/glacier interactions: an Andean example of lava dome growth through ice

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volcano/glacier interactions: an Andean example of lava dome growth through ice

Joseph S Walder

Several years ago, I reported the first well-documented example of growth of a lava dome through glacier ice: the dome-building eruption of Mount St. Helens that began in 2004. This was reported in volume 45 of Annals of Glaciology. A similar process is unfolding presently at Volcán Huila in the Colombian Andes, where a lava dome has forced its way through what is probably fairly thin ice on steep slopes. The way the ice is being bulldozed by the growing dome is reminiscent of what happened during the recent dome-building episode at Mount St Helens. Interesting, dome-collapse events were rare during the recent activity at Mount St. Helens, and have been equally rare during the present activity at Volcán Huila. This matters because dome collapse results in hot "block and ash" flows, which would aggressively erode the ice surface and produce debris flows. (Example of this phenomenon are known elsewhere.) Barring such events, heat transfer from a hot lava dome to surrounding ice is quite inefficient.

Photos of Volcán Huila may been found at this website:

http://intranet.ingeominas.gov.co/popayan/Fotograf%C3%ADas

The volcano is not accessible by ground because it's in an area controlled by the FARC guerrillas.


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Joseph S. Walder
US Geological Survey
Cascades Volcano Observatory
1300 Southeast Cardinal Court, Building 10, Suite 100
Vancouver, Washington 98683
USA
Telephone: 360-993-8948
Fax: 360-993-8980
E-mail: [hidden email]
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