Report on Nyamuragira (DR Congo) — 5 May-11 May 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 May-11 May 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2004. Report on Nyamuragira (DR Congo). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 5 May-11 May 2004. Smithsonian Institution and US Geological Survey.
1.408°S, 29.2°E; summit elev. 3058 m
All times are local (unless otherwise noted)
The Goma Volcano Observatory reported that a new eruption at Nyamuragira, which began on 8 May at 0548, was marked by strong volcanic tremor. Activity began in the volcano's summit caldera and later propagated to the N flank. A reconnaissance flight over the volcano on 9 May revealed an active lava lake in the NNE part of the Nyamuragira caldera. The lake was ~300 m in diameter and had four strong lava fountains in it. In addition, a 2-km-long eruptive fracture on the volcano's NNW flank had several lava fountains along it and two cones being built. Lava poured from many vents, forming one main flow towards the NNW. The flows remained within the National Park boundaries and did not threaten populated areas. Ash fell in several villages on the W and N flanks of the volcano.
Geologic Background. Africa's most active volcano, Nyamuragira, is a massive high-potassium basaltic shield about 25 km N of Lake Kivu. Also known as Nyamulagira, it has generated extensive lava flows that cover 1500 km2 of the western branch of the East African Rift. The broad low-angle shield volcano contrasts dramatically with the adjacent steep-sided Nyiragongo to the SW. The summit is truncated by a small 2 x 2.3 km caldera that has walls up to about 100 m high. Historical eruptions have occurred within the summit caldera, as well as from the numerous fissures and cinder cones on the flanks. A lava lake in the summit crater, active since at least 1921, drained in 1938, at the time of a major flank eruption. Historical lava flows extend down the flanks more than 30 km from the summit, reaching as far as Lake Kivu.