During a visit to Nyiragongo during 18-19 March, GVO scientists observed a thick plume engulfing the crater. Two possible emission points were noted; one was related to powerful lava and ash emissions, and the other was related to a much weaker white-pink plume. An inner active cone was visible in the crater and was at least 200 m in diameter. The cone morphology seemed to differ from when it was last seen during 26-27 February. Lava fountains rose to maximum heights of 150-200 m and as low as 50 m. Scoria ejection made observations difficult at times. Several permanent fumaroles, also observed during the previous visit, were seen in the crater.

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.

Source: Observatoire Volcanologique de Goma (OVG)