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Galeras update, 22 November 2009 22 November 2009

Posted by admin in activity reports, Colombia, eruptions, Galeras.
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Following yesterday’s eruption, the INGEOMINAS observatory at Pasto has lowered the alert level to the second-highest level of Orange, ‘eruption probable within days or weeks’. A bulletin released at 19:40 local time yesterday evening reporting the following:

Since the eruptive event of last night and following the notable increase in seismicity, the seismic activity has shown a gradual decline both in frequency and energy released. The earthquakes registered are associated principally with processes of [gas] escape although events related to the fracturing of crustal material have also been recorded. The seismicity occurs in the upper levels.

The measurements of sulphur dioxide (SO2) today show levels between low and moderate (with a maximum value of 700 tonnes/day), explicable in part to an opening of the system as a consequence of the eruption.

The eruptive event recorded yesterday reflects partial easing of forces and reduction of overpressures.

The bulletin concludes that ‘the volcanic process at Galeras remains unstable, with the presence of magmatic material in upper levels’, and warns that the volcano’s behaviour has shown that ‘in relatively short periods of time consecutive explosive events can be generated’.

Evacuation orders affecting around 7000-8000 local inhabitants were issued following the eruption yesterday. Local news sources reported that between 900 and 1000 people actually responded to the evacuation and went to the shelters.

For all our Galeras coverage: Galeras « The Volcanism Blog.

Mil personas se encuentran en albergues por erupción del GalerasEl País, 21 November 2009
Volcán Galeras amanece en alerta Naranja ante eventual erupción – Caracol Radio, 22 November 2009
Sigue alerta roja por erupción del GalerasEl Tiempo, 22 November 2009

Global Volcanism Program – Galeras – summary information for Galeras (1501-08=)
Portal Corporativo de INGEOMINAS – Instituto Colombiano de Geología y Minería
Observatorio Vulcanológico y Sismológico de Pasto – Pasto volcanological observatory main page

The Volcanism Blog