Report on Nyiragongo (DR Congo) — 15 December-21 December 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
15 December-21 December 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2004. Report on Nyiragongo (DR Congo). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 15 December-21 December 2004. Smithsonian Institution and US Geological Survey.
1.52°S, 29.25°E; summit elev. 3470 m
All times are local (unless otherwise noted)
During 29 November to 12 December, volcanic activity at Nyiragongo remained at relatively high levels. Nearly continuous high-amplitude tremor was recorded at all seismic stations on the volcano. Observations of the crater area on 9 and 10 December revealed that the level of the lava lake remained stable in comparison to previous visits and that strong lava fountaining was present. Pele's hair and scoriae fell in the area around the volcano, gas plumes rose above the volcano, and strong incandescence was visible at night. The Alert Level at Nyiragongo remained at Yellow.
Geological Summary. One of Africa's most notable volcanoes, Nyiragongo contained a lava lake in its deep summit crater that was active for half a century before draining catastrophically through its outer flanks in 1977. The steep slopes of a stratovolcano contrast to the low profile of its neighboring shield volcano, Nyamuragira. Benches in the steep-walled, 1.2-km-wide summit crater mark levels of former lava lakes, which have been observed since the late-19th century. Two older stratovolcanoes, Baruta and Shaheru, are partially overlapped by Nyiragongo on the north and south. About 100 parasitic cones are located primarily along radial fissures south of Shaheru, east of the summit, and along a NE-SW zone extending as far as Lake Kivu. Many cones are buried by voluminous lava flows that extend long distances down the flanks, which is characterized by the eruption of foiditic rocks. The extremely fluid 1977 lava flows caused many fatalities, as did lava flows that inundated portions of the major city of Goma in January 2002.