Geosphere Journal Entry

Geosphere Journal Entry

Nyiragongo Volcano Stirs (February 10, 2010)

Nyiragongo volcano is stirring again in the Democratic Republic of Congo. NASA satellites noticed increased activity in the volcano's large lava lake, while a huge plume drifted from the volcano for miles to the west. People living in the densely-populated nearby city of Goma have watched the volcano nervously since 2002, when Nyiragongo erupted violently and poured lava into the city. That eruption destroyed thousands of homes and killed dozens of people. The volcano's deadliest eruption in recent memory was in 1977, when 2,000 people died after rivers of lava burst from its crater.

The volcano is one of a pair surrounding Goma. Its twin Nyamuragira has also been active recently. Nyamuragira is a gently-sloped shield volcano. By contrast, Nyiragongo is a steep-sloped, stratovolcano with an active lava lake in its summit crater. The twin volcanoes form part of a volcanic chain along the East African Rift Zone. Rising magma steadily pushes slabs of Earth's crust apart along a divergent plate boundary marked by the rift. As the plates spread further apart, the rift valleys get deeper and longer. Eventually, they could fill with ocean water as East Africa splits off from the rest of the continent.