Nyiragongo, DR Congo

Nyiragongo, famous for its almost constant lava lake within the summit crater, it is a stratovolcano of the Virunga Volcanic complex in the East African Rift Valley and is probably the most dangerous in Africa. In total there are 8 mountains in the complex however Nyiragongo and the nearby Nyamuragira (picture below) are the only ones which remain active today.

A topographically exaggerated image of Nyiragono on the right and Nyamuragira on the left. Lake Kivu is in the foreqround with Goma the light pink area on the shore of Kivu.The image is taken from the Nasa Earth Observatory available here - http://earthobservatory.nasa.gov/IOTD/view.php?id=2164

The two most important and devastating eruptions of Nyiragongo occurred in 1977 and 2002, both of these eruptions caused many fatalities. The eruption in 1977 completely  and rapidly drained the lava lake on the 10th January 1977 creating rapid lava flows (up to ~60 mph in some cases) this rapidly overwhelmed the flanks and displaced many people present in Goma and on the flanks of the volcano. The lava lake then began to refill and on January 17th 2002 another eruption occurred when a fissure initially propogated from the top of the volcano (and later from the base) allowing the outflow of lava, the length of fissures totalled almost 20 km. Lava fountaining (or Hawaiian activity) was also present during this eruption.

Another youtube video gives an excellent overview of the area around Nyiragongo and the eruption of 2002, available here.

Sources
Shuler and Ekström, 2009. Anomalous earthquakes associated with Nyiragongo Volcano: Observations and potential  mechanisms. Journal of Volcanology and Geothermal Research 181 (3-4), pp. 219-230

Mavonga et al. 2010. Studies of crustal structure, seismic precursors to volcanic eruptions and earthquake hazard in the eastern provinces of the Democratic Republic of Congo. Journal of African Earth Sciences 58 (4), pp. 623-633

Global Volcanism Program
John Seach
Nasa EOS