Volcanos

Roundup of Global Volcanic Activity

Bardarbunga (Central Iceland): Ever since the large Holuhraun fissure eruption (Aug 2014-Mar 2015), the volcano has remained restless. Over the past months, the volcano's seismic activity has been showing a slow increase. The quakes have been concentrated at shallow depths under its central caldera, and the northeastern fissure system (in particular, near Herdubreid volcano). So far, the frequent earthquake swarms have been small and rarely contained quakes above magnitude 3; an eruption in a very near future seems unlikely for now. However, they indicate that the volcano's storage system is probably recharging with new shallow magma intrusions; a new eruption of Bardarbunga in a not too distant future (months to years) would certainly not be a big surprise.

Sakurajima (Kyushu, Japan): The activity at the volcano has been irregular. Only few, but sometime relatively strong vulcanian explosions have occurred recently, with ash plumes rising up to 17,000 ft (5 km) altitude. The Showa crater shows phases of weak continuous degassing (possibly with some ash), suggesting that deep-seated activity might be going on.

Langila (New Britain, Papua New Guinea): A mildly explosive eruption continues at the remote volcano on the western tip of New Britain Island. An ash plume and a thermal hot spot can be seen on satellite imagery.

Sinabung (Sumatra, Indonesia): The explosive / effusive eruption continues with little changes. Rising viscous lava accumulates in the summit crater where as a dome; intermittently, it produces small to moderate explosions (ash plumes rising 1-2 km) and incandescent rockfalls and/or small pyroclastic flows on the eastern side where the crater is breached. Overall, the activity (which had started in late 2013) seems to be very slowly decreasing over time.

Soputan (North Sulawesi, Indonesia): On 21 April, VSI lowered the alert level from 3 to 2 (on a scale of 1-4), following a decrease in seismic and visible activity from the volcano.

Dukono (Halmahera): Darwin VAAC reported an ash plume at 7,000 ft (2.1 km) altitude drifting SW from the volcano this morning.

Awu (North Sulawesi & Sangihe Islands): VSI raised the alert level of the volcano from 2 ("waspada") to 3 ("siaga" = eruption warning) yesterday - presumably because of increased seismic activity observed.

Ambrym (Vanuatu): Several lava lakes are currently active in Ambrym (one in Marum, two in Benbow and sometimes one in Mbwelesu craters). A recent satellite image available through GoogleEarth shows the steam plumes generated by this extraordinary activity.

Ruapehu (North Island): The alert level of the volcano was raised by a notch from 1 to Level 2 (moderate to heightened unrest) last Wednesday, Geonet informed in a special note. This was triggered by recent measurements that showed an increase in the degassing from Mt Ruapehu’s Crater Lake, a rise in temperature from 25 to 45 deg C since mid April, and ongoing moderate levels of volcanic tremor (reflecting the degassing).

Turrialba (Costa Rica): A relatively strong explosion (the strongest so far in the ongoing series of intermittent eruptions) occurred yesterday morning at the volcano at 01:18 local time. The eruption only lasted a few minutes, but generating a shower of incandescent fragments and an ash plume that rose 3 km and drifted southeast across the Central Valley. As a result, the regional Tobías Bolaños Airport in western San José was temporarily closed because of the ash plume, and reopened later in the morning. According to a first petrochemical analysis of the erupted material, most of it originates from older rock, but a small (around 5%) amount of fresh (juvenile) lava has also been detected, confirming that a new body of fresh magma has recently been intruding at shallow depths into the volcano's storage system and likely will lead to more eruptive activity in the near future.