Report on Nyamulagira (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 Nyamulagira (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.
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.