Volcanos

Roundup of Global Volcanic Activity - New Activity for the week of 25 January-31 January 2017

Chirinkotan | Kuril Islands (Russia) : Based on satellite images, SVERT reported that on 26 and 29 January ash plumes from Chirinkotan rose to an altitude of 3.5 km (11,500 ft) a.s.l. and drifted at most 105 km E and S. The Aviation Colour Code remained at Yellow (on a four-colour scale).

Erta Ale | Ethiopia : According to Volcano Discovery, visitors noted changes at Erta Ale’s lava lake during 16-20 January characterized by waves in the lava lake, intense spattering, fountaining, and rim overflows (mainly on 17 January) which traveled as far as 1 km. During the evening of 20 January explosions of very large gas bubbles ejected spatter 30 m high. Crater rim collapses affected the N crater where a new oval-shaped pit crater (150 x 30 m and 20 m depth) formed during a 24-hour period. A large collapse also occurred in the S part of the crater. The activity was accompanied by ash emissions that rose as high as 800 m. The report noted that on 21 January new fissures opened SSE from the summit caldera, producing large amounts of lava.

Satellite images acquired and processed by Planet Labs showed the new lava flows and gas-and-steam emissions from several vents (about 1.5 km SE from the overflow area at the SE caldera rim) on 23 January, and more new lava flows on 27 January. Both images showed lava flows advancing WSW, about 2.5 km S, and about 3 km NE. According to NASA's Earth Observatory, a satellite image acquired on 26 January showed two distinct infrared hotspots representing the SE lava flows. On 27 January Simon Carn stated that the eruption produced the largest SO2 emissions from Erta Ale ever measured from space.

Etna | Sicily (Italy) : INGV reported that on the morning of 15 December 2016 minor emissions of brownish ash rose from the vent in the saddle between the newer cone and the old cone of Etna's Southeast Crater (SEC). That evening some of the emissions were more energetic, ejecting incandescent material out of the crater which landed on the steep S flank of the SEC cone. Analysis of samples of the ejected rock revealed no new material, only older material from the conduit walls. During the following five weeks weak ash emissions from the vent were observed, without being accompanied by incandescence.

During the early morning of 20 January the saddle vent was again active, with small black ash puffs and thermal anomalies identified by the surveillance camera. People on the SEC observed ejected incandescent material along with ash and blocks. Cloudy weather prevented visual observations for a few days; the evening of 23 January was cloud free and mild Strombolian activity was observed, accompanied by frequent emissions of small, black ash puffs. The activity gradually intensified through the night, with some explosions launching incandescent material as far as the base of the SEC cone. Fluctuating incandescence was also visible at the 7 August 2016 vent of the Voragine (VOR) crater. The frequency of explosions and ash emissions increased on 24 January but then slightly decreased the next morning.

Takawangha | Andreanof Islands (USA) : On 27 January AVO stated that the seismic swarm that began at Takawangha on 23 January had significantly decreased during the previous day. The rate of earthquakes peaked at 190 events on 24 January and had steadily decreased to 22 detected on 27 January. Most of the events were located 7-8 km ESE, at shallow depths. The swarm continued at a decreased rate and intensity through 31 January. The Aviation Colour Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Unnamed | Tonga Islands : Based on analysis of satellite images, GeoNet reported that a submarine eruption at an Unnamed volcano (GVP volcano number 243030) about 46 km NW of Tonga’s capital Nuku’alofa began on 23 January. Activity was also identified in images from 26, 28, 29, and 31 January, characterized by discoloured water, and a volcanic plume on 31 January.