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Galeras update, 17 November 2009 17 November 2009

Posted by admin in activity reports, Colombia, Galeras.
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Galeras - image from INGEOMINAS/FAC overflight, 14 November 2009 (copyright INGEOMINAS)
The summit crater at Galeras: image from INGEOMINAS overflight, 14 November 2009 (copyright INGEOMINAS).

Colombia’s Galeras volcano remains at the second-highest level of Orange, ‘eruption likely within the next few days or weeks’. The most recent bulletin, issued on 10 November 2009, reports ‘a notable decline in the number and energy of recorded earthquakes’, with most seismic activity being associated with a combination of rock fracturing and fluid movement quakes.

The majority of the earthquakes recorded have been located in the environs of the summit crater, at depths of less than 2 km and with magnitudes of less than 2. The bulletin highlights the occurrence of ‘some’ tornillo earthquakes (long- period seismic events typically associated with pressurized fluid movements at shallow depth), noting that such events were detected during the run-up to earlier eruptions of Galeras during the period 1993-9.

No sulphur dioxide emissions have been recorded during the week 4-10 November, ‘which reflects a sealed system preventing the release of this type of gas to the atmosphere’.

The bulletin concludes by underlining that the present behaviour of Galeras ‘is similar to that recorded in the stages preceding some of the eruptive events which have taken place during the last twenty years’.

A new Galeras bulletin is due to be released by INGEOMINAS today (17 November). An overflight took place on 14 November, and the new bulletin should contain observations from that flight. In the meantime a number of photographs taken during that overflight of the summit area of the volcano (including that reproduced above) are available on the Pasto observatory website.

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

Information
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