Volcanos

Roundup of Global Volcanic Activity

Sakurajima (Kyushu, Japan): Japanese volcanologist monitoring the volcano warned that a larger eruption could occur in the near future. The alert level of the volcano was raised to the second highest, 4 out of 5, meaning that preparations for evacuations of nearby areas (within a few km from the Showa crater) are in progress. The alert was based on a strong swarm of shallow volcanic earthquakes located beneath the Showa crater. The seismic swarm started around 7 am on 15 Aug (local time), and peaked with almost 180 quakes per hour around noon. It gradually waned, but continues with weaker intensity until now. At the same time, a significant inflation of the Showa crater has been detected. These both are likely caused by the rising of a new batch of magma, which could result in a larger-then-usual eruption.

Raung (East Java): Activity has strongly decreased at the volcano. When we visited Raung during 14-15 August, we observed pulsating, often near-continuous ash emissions that produced plumes of several hundred meters. They often consisted of dark jets of ash, presumably from phreatomagmatic activity inside the conduit. This activity originated from the lower, southwestern vent of the large, double-crater new cinder cone in the eastern part of the caldera. The larger vent to the NE was almost entirely inactive, except two small, very weakly active effusive vents on its inner walls. Occasionally, glowing lava blocks were pushed out from these. The recent lava flow was no longer active. Like a giant pancake, it has completely covered the caldera floor surrounding the large cinder cone. The explosive ash emissions described above stopped during the afternoon of 14 Aug and so far, it seems have not resumed. It appears likely that the eruption has more or less come to an end.

Cotopaxi (Ecuador): The volcano started to erupt, for the first time after more than 70 years, on 14 Aug with a series of 6 very strong explosions. The volcano last erupted in 1940 and possibly 1942. A major hazard of glacier-clad Cotopaxi's eruptions are melt-water floods that can turn in to devastating lahars and threaten an area with approx. 300,000 inhabitants. The first explosion on 14 Aug occurred at 10:50 local time with an ash plume that rose approx. 8000 meters above the summit crater. During the same day, it was followed by 5 more explosions of similar or smaller size. Some of the explosions produced pyroclastic flows. The volcano calmed down a bit during yesterday, but had another explosion in the afternoon. The Ecuadorian government has declared a state of emergency for the area around the volcano and ordered evacuations. During 14 Aug, more than 400 people were evacuated from Loreto del Pedregal village on the northern foot of the volcano.