Magma
Magma is molten or partially molten rock beneath the Earth's
surface. When magma erupts onto the surface, it is called lava.
Magma typically consists of a liquid portion, often referred to as
the melt; a solid portion made of minerals that crystallized
directly from the melt; solid rocks incorporated into the magma
from along the conduit or reservoir; and dissolved gases. Magma
collects inside a volcano's magma chamber before it erupts.
Nyiragongo's magma chamber is located about 10 miles below the
surface of the Earth.