Nyamuragira volcano news & eruption updates:
Nyamuragira volcano (DR Congo): new lava lake
samedi nov. 29, 2014 02:14 | IS
The lava lake at the summit of Nyamuragira volcano in DR Congo.Photo: Benoit Smets
A satellite view of lava lakes and gas plumes from Nyamuragira and Nyiragongo volcanoes. Photo: NASA Earth Observatory
Time series of monthly SO2 amounts detected near Nyamuragira volcano. Images framed in red represent the most recenteruption. Comparison between SO2 emissions registered before and after this eruption clearly show elevated amounts of SO2 gas after the eruption. Image: Robin Campion
Volcanic gas steams from Nyamuragira volcano. Photo: Benoit Smets
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.
The Nyiragongo lava lake is presently the world’s largest lava lake with a diameter of approximately 250m. Photo: Tom Pfeiffer / www.VolcanoDiscovery.com
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.
Campion’s suggestion of an early-formed lava lake seems supported hotter-than-usual temperatures picked up by sattelites above Nyamuragira in April and late Juneand interpreted by NASA's Earth Observatory as the presence of a new lava lake. Nyamuragira’s summit also started to glow red at night in April and June, and scientists at the Goma Volcano Observatory (the Congolese scientific institute in charge of volcano monitoring) detected unusual earthquake swarms that are typical of molten rock (magma) moving underground during these months.
Benoit Smets, a volcanologist at the European Center for Geodynamics and Seismology in Luxembourg. is however not convinced that the Nyamuragira lava lake formed that long ago. Last July, United Nations peacekeepers dropped Smets and an international group of scientists off at the volcano’s summit by helicopter, to check on the crater. Their October 21 report in Eos, the weekly newspaper of the American Geophysical Union, describes observations of lava fountains but no sight of a lava lake.
This disagreement reflects both science-in-progress (varying scientific monitoring methods might lead to different interpretations) and the difficulty of working in the DR Congo (instruments can’t be left in the field for safety reasons and dozens of armed groups continue to fight in the area). The debate whether or not there is a lava lake at Nyamuragira was finally settled when on the 6th of November a helicopter survey of the Goma Volcano Observatory reported visual confirmation of an active lava lake.
Likely evolution of this volcanic activity
Benoit Smets describes the present volcanic activity at Nyamuragira as ‘a very small, bubbling lava lake’. And although the churning lava seems to come and go, scientists think within a few years to decades the volcano may spawn a long-lived lava lake similar to the one at neighbouring Nyiragongo volcano.
Both Nyamuragira and Nyiragongo can show volcanic activity that threatens nearby towns such as Sake and Goma. The January 2002 eruption of Nyiragongo, for example, destroyed large parts of Goma and left 200,000 people homeless. Nyiragongo’s closer proximity to local communities does, however, make it more of a hazard than Nyamuragira which is surrounded by a national park. Nyamuragira’s immediate threat is therefore not so much lava flows or volcanic debris but acid rain from its volcanic gas which can corrode roofs, destroy crops and affect human health.
lundi, août 04, 2014
It is uncertain whether the eruption at Nyamuragira still continues, i.e. whether the new lava lake detected in July still exists. ... [details]
lundi, juil. 07, 2014
The new eruption continues in the form of a lava lake in the summit caldera. No evidence of lava flowing on the flanks of the giant volcano is availabe. ... [details]
jeudi, juil. 03, 2014
A new eruption is occurring at the volcano. A lava lake has appeared in the main pit inside its summit caldera, but so far, reports of lava flows (presumably from flank vents) on the northern slope of Nyamuragira could not be verified. ... [details]
dimanche, avril 13, 2014
News started to spread on twitter and other media that a new eruption of the volcano started today, including pictures from the 2010 eruption as (false) evidence. ... [details]
samedi, avril 12, 2014
No confirmation whether a new eruption at the volcano has started is available yet, but MODIS satellite data show a thermal hot spot near the NE rim of the summit caldera and a strong SO2 plume is being detected coming from the area. ... [details]