Ecuador’s Cotopaxi volcano – increased seismic activity, volcanic unrest after 73 year slumber

June 2015 – ECUADOR – The volcano has been showing signs of unrest. Since mid-April this year, and particularly during May, a marked increased in earthquakes and SO2 emissions have been detected, which could be signs of a magma intrusion beneath the volcano. During May, about 3000 local earthquakes were recorded, a significant increased compared to April (628 quakes), and more than during the last seismic crisis in 2001-02. In particular, long-period earthquakes related to internal fluid movements have shown an increase in May. Most quakes were located in areas north and northeast of the volcano’s summit, at two depth layers, one at shallow 3 km and others at deeper depths of up to 14 km.

In addition, SO2 emissions have shown an increased from normal values of approx. 500 tons / day to 2500-3000 tons per day. At the crater, fumarolic activity has increased during May. During the weekend of 22 and 23 May, sulfur smell the upper northern flank was very intense. Very slight deformation has occurred on the N and NE flanks, suggesting a trend towards inflation, IGPEN reported. For now, the signs of volcanic unrest are small and there is no indication that a new eruption is imminent, but the current unrest could be a medium to long term precursor to a possible new eruption, which would be the first since 1942. –Volcano Discovery