According to the UN Office for the Coordination of Humanitarian Affairs (OCHA), several earthquakes were felt by the population near Nyiragongo on 28 and 29 January. The earthquakes ranged in intensity from small to large. No volcanic tremor, indicating magma movement, was recorded. On 29 January heavy rain caused large amounts of steam to rise from cooling lava. The increase in steaming led to several false reports of renewed volcanism. The pH of Lake Kivu was measured to be the same as prior to the 17 January eruption. The volcano remained at Alert Level Yellow (second lowest on a four-color scale).

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.

Sources: ReliefWeb, US Agency for International Development / Office of US Foreign Disaster Assistance, UN Office for the Coordination of Humanitarian Affairs (OCHA)