Report on Nyamuragira (DR Congo) — February 1977
Natural Science Event Bulletin, vol. 2, no. 2 (February 1977)
Managing Editor: David Squires.
Nyamuragira (DR Congo) Additional information about late-December 1976 activity
Please cite this report as:
Global Volcanism Program, 1977. Report on Nyamuragira (DR Congo) (Squires, D., ed.). Natural Science Event Bulletin, 2:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.NSEB197702-223020.
1.408°S, 29.2°E; summit elev. 3058 m
All times are local (unless otherwise noted)
The eruption of Nyamuragira began at about 1540 ["about 1200" below] on 23 December, from a new flank crater 8 km SW of the summit. Lava fountains 150-200 m high formed a 70-m spatter cone around the vent. Two lava flows were extruded, one that extended about 3 km to the SW, the other about 1 km to the W. The eruption was continuing as of 31 December.
More than 10 times the normal number of volcanic earthquakes were recorded on 11 December from Lwiro (~l00 km SSW of the volcano), and significantly more than the normal number on 12, 21, and 22 December. The March-May 1971 eruption of Nyamuragira took place at Rugarama, on the NW flank (Pouclet and Villeneuve, 1972) rather than the SW flank or the summit crater as reported elsewhere.
Reference. Pouclet, A., and Villeneuve, M., 1972, L'Eruption du Rugarama (Mars-Mai, 1971) au Volcan Nyamuragira: Bulletin Volcanologique, v. 36, p. 200-221.
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.
Information Contacts: S. Ueki, Institute de Recherche Scientifiques Afrique Centrale (IRS).