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Report on Nyamulagira (DR Congo) — 12 May-18 May 2004


Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
12 May-18 May 2004
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2004. Report on Nyamulagira (DR Congo). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 12 May-18 May 2004. Smithsonian Institution and US Geological Survey.

Weekly Report (12 May-18 May 2004)


DR Congo

1.408°S, 29.2°E; summit elev. 3058 m

All times are local (unless otherwise noted)

During a flight over Nyamuragira on 12 May scientists noted that volcanic activity remained strong, but stable. The lava lake at the volcano's summit was in a ~15-m-deep pit and its activity had greatly decreased in comparison to observations on 9 May. The lake's surface had crusted over, with three vents exhibiting Strombolian activity (lava spattering and overflows producing short lava flows). In addition, the eruptive fracture on the volcano's NNW flank had four main cones with very active lava fountains reaching heights of 30-50 m. Small lava flows from the cones coalesced into one wide lava flow, covering a large area to a distance of ~12 km. The TOMS (Total Ozone Mapping Spectrometer) Volcanic Emissions Group reported that sulfur-dioxide clouds were visible on TOMS satellite imagery since the eruption began on 8 May, although some of the gas may be attributed to emissions from neighboring Nyiragongo (~13 km SE from Nyamuragira).

Geological Summary. Africa's most active volcano, Nyamulagira (also known as Nyamuragira), is a massive high-potassium basaltic shield about 25 km N of Lake Kivu and 15 km NE of the steep-sided Nyiragongo volcano. The summit is truncated by a small 2 x 2.3 km caldera that has walls up to about 100 m high. Documented eruptions have occurred within the summit caldera, as well as from the numerous flank fissures and cinder cones. A lava lake in the summit crater, active since at least 1921, drained in 1938, at the time of a major flank eruption. Recent lava flows extend down the flanks more than 30 km from the summit as far as Lake Kivu; extensive lava flows from this volcano have covered 1,500 km2 of the western branch of the East African Rift.

Sources: Observatoire Volcanologique de Goma (OVG), OMI Sulfur Dioxide Group