Volcanos

Roundup of Global Volcanic Activity

Copahue (Chile/Argentina): Activity, both internal and external, has picked up at the volcano. Small, intermittent ash emissions have been observed during the past days, accompanied by a significant increase in tremor related to fluid movements within the volcanic edifice. During an overflight on 13 Sep, SERNAGEOMIN scientists had found that the acid lake was still present in the El Agrio crater, despite the incandescence visible sometimes at night caused by hot gasses. Fresh sulphur deposits were seen covering snow around the crater, suggesting that at least some part of the erupted gasses originate from magma underneath and not only from the shallow hydrothermal system. Signs of small phreatic explosions were also detected, SERNAGEOMIN reported in a bulletin on 22 Sep. Between 13 and 22 September, the Lake level began to decrease. Volcanologists believe that the reason for these phenomena is that magma has migrated closer to the surface, although not reached it yet. Whether or not it will, remains to be seen.

Aso (Kyushu): After the strong explosion on 14 Sep, the volcano has been rather calm, but continues to emit dilute ash plumes. The volcano remains at level 3 (out of 5) and access to the Nakadake crater closed.

Cotopaxi (Ecuador): Visible activity of the volcano has been relatively low during the past week. Only a strong steam plume mixed with low ash contents has been emitted, but there has been a significant change: incandescence has now become visible from the crater. According to scientists from IGEPN, the glow originates from high-temperature gasses. However, this suggests that magma continues to approach the vent, and that the eruption might now be about to become magmatic. The latter means that the volcano starts to erupt fresh magma, not, only older fragmented material during phreatic (steam-driven) ash explosions as it has been doing so far. According to IGEPN, this could be premonitory of a new eruptive phase characterized by small to moderate explosions that could expel incandescent blocks outside the crater, accompanied by new ash emissions.

Michael (United Kingdom, South Sandwich Is): A hot spot has been detected on Saunders Island on MODIS satellite data on 30 Sep. According to the South Sandwich Islands Volcano Monitoring Blog, this is most likely an indicator of volcanic activity on Mount Michael volcano. The remote South Sandwich Islands in the south Atlantic Ocean lack human activity. A hot spot was previously detected on Saunders Island during the 28th, the 30th, and the 31st August 2015.