Cotopaxi, Ecuador : decrease of the external activity.

Cotopaxi, Ecuador : decrease of the external activity.

During the last week, on the Cotopaxi volcano, there was a decrease of the external activity, which is characterized mainly by gas columns, white, which reached up to 2 km above the crater. The presence of ash was lower than previous weeks possibly indicating the end of the phase, which began on October 3. It was recorded between 50-100 volcano tectonic earthquakes (VT) per day, which represents a slight increase from the previous week. The great majority of these types of VT events are small amplitudes. SO2 levels gases were at least 2,500 tonnes / day.

There were sporadic episodes of tremor emission and some small explosions.

The visual observation conditions were variable. However emission columns last week were up to 2000 m but usually less than 1000 m above the crater with low load of ash. The wind direction varied between Nortd-West and South, predominantly to the west. The brightness of the crater was also observed during clear nights.

The inclinometer VC1 deformation shows a diagram less pronounced compared to previous months. The trend in recent weeks of October showed a slight increase in its slope can be related to the slight increase in the number of recorded VT events.
During the last week small falls of ash fell in the Cotopaxi National Park, while in the more remote areas these falls were minimal. No major changes were observed in the size of the ash (very thin) or components (mainly from the pipe material, possibly slightly juvenile).

November 09, 2015. Cotopaxi, Ecuador :

Source : IGEPN

Photo : Jean-Luc Le Pennec, IRD-IGEPN

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