SERNAGEOMIN raised the alert level of Chilean Copahue volcano to orange on March 20 [still active] after an increase in seismic activity. A pulse of volcanic tremor was detected that could indicate magma moving into the volcano's plumbing system.
On the surface, no unusual activity has been seen at the volcano so far, except that an increase in SO2 emissions (approx 2 300 tons / day) was measured. This supports the idea that magma has risen under the edifice, Volcano Discovery reports.
Whether this activity is followed by new eruptive activity remains to be seen. In most cases, intrusions of magma under volcanoes do never reach the surface, i.e. produce eruptions.
ONEMI (Civil Defense) published a bulletin stating that civil alert remains at yellow for the highest risk areas, in particular the most proximal areas around the volcano itself, but also include the city of Alto Biobío located 40 km west of the volcano, because it is at the mouth of a valley that drains Copahue on the north side and therefore, a potential pathway for mud flows that could occur during an eruption.
Featured image: Copahue on March 21, 2014. Image credit: SERNAGEOMIN