Bardarbunga (Iceland): These two images were posted on the twitter account of the University of Iceland after their recent field expedition. As the lava field continues to expand, new branches of red hot rivers reach its edge and cascade down on the sandy plain below in a spectacular ‘water’fall of glowing lava. Scientists report that by now the Holuhraun lava field covers almost 75 square kilometres which represents an area bigger than the Reykjavik metropolitan area.
The intensity of the eruption declined so that the present amount of emitted lava is only a quarter of what it was at the eruption’s most intense phase. But according to Ármann Höskuldsson, volcanologist at the University of Iceland Earth Science Institute, there are no indications that the volcanic activity will stop anytime soon. He points out that it remains a very intense eruption despite the recent (temporarily?) weakening of its activity. Scientists observed fluctuations in the eruption plume last week due to sporadic emission of powerful lava jets. The lava flow discharge pulsated accordingly.
The exact amount of magma flowing from the Bárðarbunga magma chamber through the intrusive dike below the Vatnajökull glacier and eventually erupting in Holuhraun is presently unclear. The Icelandic Broadcasting Service (RUV) reports it to be 130 cubic metres asecond, whereas the newspaper Morgunblaðið (mbli.is) estipmates it to be between 60 and 100 cubic metres per second.
Nyamuragira (DRCongo): For the first time in 75 years, a new lava lake appeared on some of Africa’s most active stratovolcanoes: Mount Nyamuragira in the Democratic Republic of Congo. The neighbouring volcanoes of Nyamugira and Nyiragongo are both part of the Virunga volcanic chain in the East African Rift, situated along DR Congo’s border with Rwanda. They are famous as two of the few volcanoes on Earth that have sustained lava lakes for several decades. The previous lava lake at Nyamuragira emptied in 1938 as its lava poured out of the summit and flowed more than 30 kilometres down to Lake Kivu. The new lava lake seems to have formed at the bottom of the 500 m deep crater that was left behind by this 1938 lava flood.
Nyamuragira’s last eruption started in November 2011 and ended in March 2012 by the partial emptying of the magma chamber through the effusion of large lava flows. This eventually resulted in the collapse of the pit crater, an event after which the magma is likely forced to follow a new route higher up to the volcano’s summit. Such reconstruction of the volcano’s plumbing system with transport of magma higher in the volcano’s cone could trigger the formation of a lava lake. Nyamuragira’s past eruptions all seem to follow a typical eruptive cycle of lava being progressively emitted from the volcano’s base to its summit, ending in the formation of a lava lake.
But when exactly did this lava lake form?
Robin Campion, volcanologist at the Universidad Nacional Autónoma de México in Mexico City, has been monitoring the emission of sulphur dioxide gas in Nyamuragira’s surroundings during and after the most recent 2012 eruption. As expected, SO2 emissions were very high throughout the volcano’s last eruption. After the pit crater collapse that marks the end of this eruption, however, sulphur dioxide levels remained high – something Campion could only explain by the formation of a lava lake. He published his findings in the November 7 issue of the Journal of Geophysical Research Letters.
Fogo (Cape Verde): Activity, after having slowed down a bit yesterday, picked up again this morning, as a new vent opened above the eruption fissure.
Lava fountaining and associated lava effusion mainly occur from the lower vent, while the upper one shows strombolian explosions, strong degassing and ash emissions. As typical for flank eruptions, eruptive activity has by now concentrated to and continues from two vents (as compared to 6 active ones on the first day):
The main lava flow, as well as several secondary ones that start as overflows in the vent area, remain well alimentated. The lava flows have covered approx. 400 hectars of land, including 26 hc of farmland.
Zhupanovsky (Kamchatka, Russia): A moderately strong ash emission occurred this morning. A plume at 20,000 ft (6 km) drifted east. Weaker ash venting continued afterwards. (Tokyo VAAC).
Aso (Kyushu): Activity at the volcano picked up and went through an intense phase of strong, continuous ash emissions Wednesday. An ash plume rose to approx. 3 km altitude, according to Tokyo VAAC.
A video showed incandescent ash-rich fountains from the crater, confirming that new magma has arrived there, i.e. a new magmatic eruption has formally started at the volcano:
After the most intense phase, activity calmed down again and turned into strong steaming mixed with minor ash emissions.
Ambrym (Vanuatu): active lava lakes in several craters (updated 14 Aug 2013)
Aso (Kyushu): intermittent moderate to strong ash emissions (updated 28 Nov 2014)
Bagana (Bougainville Island, Papua New Guinea): ash emissions, lava dome growth (updated 10 Nov 2014)
Bardarbunga (Iceland): Ongoing lava fountain from Baugur crater, subsidence of Bárðarbunga caldera and seismic activity (updated 18 Sep 2014)
Barren Island (Indian Ocean): intermittent activity, likely strombolian-type and/or lava flows (updated 4 Feb 2014)
Batu Tara (Sunda Islands, Indonesia): strombolian explosions, ash plumes up to 500 m, extrusion of a small lava dome with rockfalls (updated 4 Nov 2014)
Colima (Western Mexico): new lava flow on SW flank (updated 22 Nov 2014)
Dukono (Halmahera): thermal anomaly, probably small explosive activity in summit crater (updated 25 Nov 2014)
Erebus (Antarctica): active lava lake in summit crater (updated 21 Jan 2012)
Erta Ale (Ethiopia): active lava lake in northern pit crater, active hornito with intermittend flow in southern crater (updated 11 Jan 2013)
Fogo (Cape Verde): lava fountaining (updated 28 Nov 2014)
Fuego (Guatemala): strombolian explosions from summit crater, intermittent lava flows (updated 14 Nov 2014)
Ibu (Halmahera, Indonesia): stromolian and phreatomagmatic explosions (updated 14 Nov 2014)
Karymsky (Kamchatka): occasional small explosions, thermal anomaly (updated 4 Oct 2014)
Kilauea (Hawai’i): new lava flow from vents on NE flank of Pu’u ‘O’o (updated 13 Aug 2013)
Manam (Papua New Guinea): degassing, occasional ash venting (updated 28 Aug 2013)
Marapi (Western Sumatra, Indonesia): sporadic explosions (updated 27 Mar 2014)
Nishino-shima (Volcano Islands, Japan): growing island (updated 11 Oct 2014)
Nyiragongo (DRCongo): active lava lake in summit crater (updated 26 Feb 2014)
Ol Doinyo Lengai (Tanzania): effusion of natrocarbonatite lava inside the crater (updated 8 Jul 2013)
Poas (Costa Rica): phreatic explosions (updated 14 Oct 2014)
Rabaul (Tavurvur) (New Britain, Papua New Guinea): lava fountains, ash emissions from Tavurvur cone (updated 12 Sep 2014)
Reventador (Ecuador): new lava flow on upper NW flank (updated 22 Nov 2014)
Sakurajima (Kyushu, Japan): ash venting, intermittent explosions (updated 5 Nov 2014)
Sangeang Api (Indonesia): growing lava dome & lava flow (updated 7 Jul 2014)
Santiaguito (Guatemala): generation of hot lahars (updated 14 Nov 2014)
Semeru (East Java, Indonesia): growing lava dome, lava flow, strombolian activity (updated 26 Nov 2014)
Shishaldin (United States, Aleutian Islands): mild explosive activity, intermittent more intense phases (updated 24 Nov 2014)
Shiveluch (Kamchatka): growing lava dome, incandescent avalanches, occasional explosions (updated 25 Nov 2014)
Sinabung (Sumatra, Indonesia): continuing pyroclastic flows (updated 19 Nov 2014)
Slamet (Central Java): intense strombolian explosions (updated 13 Sep 2014)
Stromboli (Eolian Islands, Italy): weak strombolian activity at summit vents (updated 22 Nov 2014)
Suwanose-jima (Ryukyu Islands): strombolian activity in summit crater (updated 14 Nov 2014)
Tungurahua (Ecuador): moderate to strong strombolian explosions from central crater (updated 25 Sep 2014)
Turrialba (Costa Rica): occasional ash emissions (updated 17 Nov 2014)
Ubinas (Peru): degassing, sporadic small explosions and ash venting (updated 11 Sep 2014)
Yasur (Tanna Island, Vanuatu): ash emissions, weak strombolian explosions (updated 14 Aug 2013)
Zhupanovsky (Kamchatka, Russia): degassing, last eruption ended mid Oct 2014 (updated 28 Nov 2014)