Report on Nyiragongo (DR Congo) — 12 February-18 February 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 12 February-18 February 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Nyiragongo (DR Congo). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 12 February-18 February 2003. Smithsonian Institution and US Geological Survey.
1.52°S, 29.25°E; summit elev. 3470 m
All times are local (unless otherwise noted)
Beginning around 10 February volcanic activity increased at Nyiragongo. Fine ash covered cars in the city of Goma and at 1142 a long-period earthquake occurred for more than 2 minutes that was followed by several small events and an increase in tremor amplitude. Residents near the volcano noticed an increase in plume height, a change in plume color from white to black, and a sustained rain of ash and Pele's hair. As of the 14th, Pele's hair continued to fall in Goma and an ash plume was visible rising at least 5 km above the crater. At this time seismicity was probably lower than the previous week. GVO stated that the Pele's hair that fell in Goma was produced by lava fountaining inside Nyiragongo's crater. Residents in Goma and surrounding villages experienced a water shortage due to the contamination of rain water, which is their only source of water.
According to the MODIS Thermal Alerts website, thermal alerts have been visible at Nyiragongo every month since June 2002. Two alert pixels were visible at the volcano on 13 February.
Geologic Background. 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. In contrast to the low profile of its neighboring shield volcano, Nyamuragira, 3470-m-high Nyiragongo displays the steep slopes of a stratovolcano. 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.
Sources: Goma Volcano Observatory (GVO), The Open University Volcano Dynamics Group