Report on Nyamulagira (DR Congo) — October 2003
Bulletin of the Global Volcanism Network, vol. 28, no. 10 (October 2003)
Managing Editor: Edward Venzke.
Nyamulagira (DR Congo) Long-period earthquake swarms
Please cite this report as:
Global Volcanism Program, 2003. Report on Nyamulagira (DR Congo) (Venzke, E., ed.). Bulletin of the Global Volcanism Network, 28:10. Smithsonian Institution.
1.408°S, 29.2°E; summit elev. 3058 m
All times are local (unless otherwise noted)
During the 3-month period from 2 August to 8 November 2003, seismicity in the Nyamuragira area was dominated by long-period (LP) events localized along a main NNE-SSW fracture between Nyamuragira and Nyiragongo volcanoes. Intermittent swarms of LP events (60-80 events each time) occurred on Nyamuragira two to three times per week. A larger swarm was observed on 23 July (100 LP events). This activity remained fairly stable for the whole period. Earthquakes related to fracturing continued, mainly S of Nyiragongo (N of Lake Kivu ) and NE of Nyamuragira. No noticeable deformation change has been recorded along the fracture system.
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.
Information Contacts: Observatoire Volcanologique de Goma, Departement de Geophysique, Centre de Recherche en Sciences Naturelles, Lwiro, D.S. Bukavu, DR Congo.