Report on Nyamulagira (DR Congo) — 26 October-1 November 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
26 October-1 November 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Nyamulagira (DR Congo). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 26 October-1 November 2005. Smithsonian Institution and US Geological Survey.
1.408°S, 29.2°E; summit elev. 3058 m
All times are local (unless otherwise noted)
Beginning on 23 October, GVO recorded heightened seismic activity along the East African Rift and around the Virunga volcanoes when a swarm of long-period earthquakes occurred N of Nyamuragira. More than 140 events were recorded at a station 19 km E of the volcano. On 27 October at 1500, another swarm of long-period earthquakes began beneath the same area. More than 300 events were recorded until at least 28 October. At 2010, a M 4.5 tectonic earthquake occurred N of Lake Tanganika, which was followed by several aftershocks. GVO noted that this activity reinforces the likelihood of an eruption in the near future, but volcanic activity would not pose a threat to inhabited areas. The Alert Level for the nearby city of Goma remained at Yellow.
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.