Report on Nyamuragira (DR Congo) — 26 February-4 March 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 26 February-4 March 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Nyamuragira (DR Congo). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 26 February-4 March 2003. Smithsonian Institution and US Geological Survey.
1.408°S, 29.2°E; summit elev. 3058 m
All times are local (unless otherwise noted)
A seismic crisis began at Nyamuragira during the evening of 26 February, with an increase in both long-period and tectonic earthquakes and an increase in tremor amplitude. GVO received reports from residents near the volcano of possible eruptive activity, but GVO scientists' view of the volcano was obscured by clouds. Spasmodic tremor was recorded on 19 and 23 February, lasting several tens of minutes. According to GVO, this seismicity was located very close to the surface. They stated that activity at Nyamuragira was changing very rapidly and an eruption may occur in a matter of days or weeks.
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.
Source: Observatoire Volcanologique de Goma (OVG)