Cause of Volcanoes A volcano is
an opening in the earth's crust through
which molten lava, ash, and gases are ejected. Volcanoes are formed when magma from inside of the earth works
its way
through the crust and creates gas. This gas builds up pressure. When
pressure is to much for a mountain to stand, it explodes, and a volcano is born. This, however, does not lead to a large scale eruption, so there is still time
for evacuation.
Magma
Magma is molten rock
located below the surface the Earth. Magma is created when, in the Earth, there is a sudden decrease
in pressure. This process occurs, called decompression melting, that heats up the rocks
past melting point, and melting the already heated rocks around it. Magma
rises from the depths of the earth, gathers in a pool, in a weak area of the
rock.
This is the magma chamber. Eventually,
but not always, magma erupts
onto the surface. Large earthquakes can predict
rising magma and the volcano
may grow in size before an eruption.
cated below the surface the Earth. Magma is created when, in the Earth, there is a sudden decrease
in pressure. This process occurs, called decompression melting, that heats up the rocks
past melting point, and melting the already heated rocks around it. Magma
rises from the depths of the earth, gathers in a pool, in a weak area of the
rock.
This is the magma chamber. Eventually,
but not always, magma erupts
onto the surface. Large earthquakes can predict
rising magma and the volcano
may grow in size before an eruption.