Nyamuragira volcano (DR Congo), update: eruption continues with active lava lake and lava flow from new NE vent
Friday Jan 27, 2012 15:55 PM | BY: T
The second NE vent of the eruption of Nyamuragira seen on 22 Jan 2012. The strong glow is from the active lava lake inside its central vent.
During our recent expedition, we visited Nyamuragira's ongoing eruption during 22-25 January, and found that the eruption is still going on strongly, but somewhat less intense than during the first 1-2 weeks in January.
NASA image of the lava flows from the eruption taken on 23 Jan 2012.
The second vent complex, which had started to form at the NE end of the eruptive fissure in late Dec or early Jan with about one week of constant fountaining, consists of probably 3 coalescent cones.
The middle and largest of them contained a crater filled with boiling lava, i.e. a small lava lake, which was strongly spattering every few seconds. The lava lake itself was not visible, but could be inferred from the strong glow and the hissing degassing noise of exploding gas bubbles that ejected liquid spatter bombs in all directions.
Some of the ejections reached up to about 200 m height and individual bombs reached the base of the cone.
A large recent and still hot lava flow field from this vent extends for many kilometers to the N as far as one could see. A lava flow exits the vent area in a tube, and is visible from a row of skylines. Several small breakouts formed secondary flows, usually short-lived in various locations in the field during our visit. A large breakout, probably corresponding to the current end of the lava tube, is seen about 2 km north of the cone, feeding a large lava flow, about 20 m wide, which snakes northward until it was difficult to see details in the distance. Burning forest could be seen to the NNE.
The older westerly vent complex that had been active in Nov-Dec was only degassing and there were large ring-fractures visible at the summit rim, probably caused by gravitational setting of its central parts.
The area north of the eruptive fissure shows impressive surface deformation by fissures along parallel faults creating a bizarre and complex pattern of small grabens and uplifted blocks, exposing the pre-eruptive strata of scoria and lava flow layers. These correspond to surface fracturing during the initial stage of near-surface dike injection.
A set of photos will be published here soon.
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