Mount Nyiragongo is an active stratovolcano with an elevation of in the Virunga Mountains associated with the Albertine Rift. It is located inside Virunga National Park, in the Democratic Republic of the Congo, about north of the town of Goma and Lake Kivu and just west of the border with Rwanda. The main crater is about two kilometres wide and usually contains a lava lake. The crater presently has two distinct cooled lava benches within the crater walls - one at about and a lower one at about . Nyiragongo's lava lake has at times been the most voluminous known lava lake in recent history. The depth of the lava lake varies considerably. A maximum elevation of the lava lake was recorded at about prior to the January 1977 eruption - a lake depth of about . A recent very low elevation of the lava lake was recorded at about . Nyiragongo and nearby Nyamuragira are together responsible for 40% of Africa's historical volcanic eruptions.