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Nevado del Huila: an overview of activity, 21-27 October 2009 28 October 2009

Posted by admin in activity reports, Colombia, Nevado del Huila.
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The Colombian state geological service INGEOMINAS has published an overview of activity at Nevado del Huila volcano over the last few restless days: Reporte de actividad volcán Nevado del Huila, 27 oct 2009, available at the Observatorio Popayán website. Translation as follows.

Report of activity at Nevado del Huila volcano, 27 October 2009

The level of activity at the volcano continues at LEVEL ORANGE (II): ERUPTION PROBABLE WITHIN DAYS OR WEEKS.

From analysis of the information obtained via the monitoring network of Nevado del Huila volcano in the week of 21 to 27 October 2009, the INGEOMINAS Popayán volcanological and seismological observatory reports that:

– In the present week a total of 1004 seismic events have been recorded: 119 related to the fracturing of rock, 847 to fluid dynamics within the volcanic conduits, 13 were hybrid type events and 25 were pulses of tremor associated with the escape of gases and ash to the surface.

– During the week various pulses of spasmodic tremor associated with the escape of gases and ash to the surface were recorded, particularly those occuring on Friday 23 October at 04:35 (09:35 UTC) and Saturday 24 October at 12:10 (17:10 UTC). Related to these events, reports of ash fall were received from several municipalities in Cauca, Huila and Valle de Cauca. Similarly, a sulphur smell has been reported by passengers on commercial flights and residents of towns around the volcano.

– In an overflight carried out by observatory personnel on Friday 23 October with the support of the Colombian Air Force the volcanic edifice was seen to be completely covered with ash, two principal focuses of emission of gases and ash on the surface were seen, located in the upper part of Pico Central, and the extrusion of new magmatic material was visible towards the surface in the extreme north of the dome constructed in November 2008.

– In images captured via the webcam during the week, intense degasification of the system with pulsating emission of ashes at the surface was observed. The directions of the columns fluctuated in accordance with the prevailing winds in the area. In the same way, the VAAC has issued eight reports of sightings through satellite imagery that show columns of ash up to 5000 metres altitude over the summit of the volcano.

– The images captured by the AURA-OMI satellite and published by the NOAA allow observation of the continuing discharge of SO2 during 21, 22, 23, 25 and 26 October, with a maximum of 7793 tonnes/day recorded on Monday 26 October. These images match up with the record of continuous tremor observed during the week.

– On Monday 26 October SO2 was measured through the MovilDOAS system between the town of Miranda (Cauca) and the city of Popayán. An SO2 flow of 3766 tonnes/day was calculated, with dispersion towards the south-west of the volcano. In measurements of SO2 carried out by the ScanDOAS station in the city of Cali those of today stand out, in which the flow is calculated at 4551 tonnes/day in a column dispersed towards the north-west of the volcano.

– Because of the foregoing, it is concluded that the volcanic system continues to show unstable behaviour, with a predominance of processes associated with fluid dynamics, which involve the escape of ash and gases to the surface. For this reason, it is recommended that particular attention is paid to the evolution of the current phenomena, because of the possibility of movement towards a state of higher activity.

INGEOMINAS will continue to monitor and report in a timely manner on any changes that may take place.

[End of INGEOMINAS report.]

For all our Nevado del Huila coverage: Nevado del Huila « The Volcanism Blog.

Information
Global Volcanism Program: Nevado del Huila – summary information for Nevado del Huila (1501-05=)
INGEOMINAS Popayán – main page for the Observatorio Popayán, which monitors Nevado del Huila

The Volcanism Blog