Lava
Lava is the word for magma when it erupts onto the Earth's
surface. Geologists also use the term to describe the solidified
deposits of lava flows. Lava is from the Italian word for stream,
which is derived from the verb lavare, to wash. The type of
lava erupted by Nyiragongo and many volcanoes in the East Rift
zone of Africa, called alkaline lava, has an extremely low
viscosity, making it almost as fluid as water. Alkaline lava has a
melting temperature in excess of 2,000 degrees Fahrenheit. The
fluidity and extreme temperature of Nyiragongo's lava make for a
particularly deadly combination during eruptions.