Where magma erupts on the surface of the earth, temperatures are lower and cooling of the magma takes place much more rapidly. This is the extrusive or volcanic environment and results in extrusive or volcanic igneous rocks.
Magma is created when rocks are at the correct temperature and pressure to cause melting also know as passing the Liquidus (aka melting point with respect to pressure and temperature).
Magma is created from the subduction of cold, dense lithospheric plates into the hot rock of the mantle. The water in the subducting slab lubricates the rock and lowers (with respect to temperature) the liquidus causes the melting of the rocks, creating rising plumes of magma into the crust.
Magma is also created in massive quantities at divergent plate boundaries, know as mid-ocean ridges, where decompression melting of mantle rock occurs where the crust is being removed from the mantle. The magma and, to a much smaller extent, the mantle then rises to fill in the gap between the spreading ocean plates.
Additionally, magma is also created at mantle plumes, where there are stationary locations of rising heat from deep in the Earth's interior. As the hot rock rises, it experiences a decrease in pressure allowing it to pass the liquidus and undergoes melting.
Magma starts to build up when the pressure of a volcano reaches the surface of it, and then the mountain starts to 'bubble up.'
by the magma being too hot
viscosity of magma build up of gases
Eruption
volcanoes
volcano
The viscosity (resistance to runniness) of magma affects the rate at which it rises up through the mantle. High viscosity magma rises slowly because it's thick and sticky, and low viscosity magma rises quickly (like the big island of Hawaii). Low viscosity magma is less likely to erupt explosively because it has less chance to build up pressure. High viscosity magma is the opposite and a lot of pressure has to build up before it will erupt, which causes a more explosive/sudden eruption.
magma rises up out of a volcano by the build up of pressure
build up of magma
Yes.
1. Magma in the magma chamber begins to build up 2. Magma goes up into the pipe 3. The volcano erupts
Eruption
viscosity of magma build up of gases
in the magma chamber gasses build up. while it is silent its building up theses ezplosive gasses build up and explode.
volcanoes
volcano
1. Pressure in the magma chamber begins to build up. 2. The pressure forces the magma to go up through the vent. 3. Then it will erupt
The viscosity (resistance to runniness) of magma affects the rate at which it rises up through the mantle. High viscosity magma rises slowly because it's thick and sticky, and low viscosity magma rises quickly (like the big island of Hawaii). Low viscosity magma is less likely to erupt explosively because it has less chance to build up pressure. High viscosity magma is the opposite and a lot of pressure has to build up before it will erupt, which causes a more explosive/sudden eruption.
The magma build up was so great it caused it to explode.