Report on Nyamuragira (DR Congo) — July 1986
Scientific Event Alert Network Bulletin, vol. 11, no. 7 (July 1986)
Managing Editor: Lindsay McClelland.
Nyamuragira (DR Congo) Reported S-flank eruption
Please cite this report as:
Global Volcanism Program, 1986. Report on Nyamuragira (DR Congo) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 11:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198607-223020.
1.408°S, 29.2°E; summit elev. 3058 m
All times are local (unless otherwise noted)
An eruption began on 16 July at 1500 [but see 11:8] from a fissure near the 1976 eruption site of Harakandi, on the SSW flank at ~2,200 m elevation. High lava fountains produced a lava flow to the SW. By 18 July, lava fountains were still 200 m high, and at the end of one week, the lava flow had extended 10 km SW toward Lake Sake, before ponding and spreading. Degassing was abnormally high from the two vents formed on the eruptive fissure, compared to previous eruptions. Inspection of 11-20 July satellite imagery did not reveal an eruption plume, but heavy weather clouds obscured the area.
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: M. Krafft and K. Krafft, Cernay, France; W. Gould, NOAA.