What creates the Eruption of a volcano? {fully described}?

Answer 1

Volcanoes:
There are several processes in Plate Tectonics that cause volcanism, but they result in two main types of volcanism.

Volcanism in subduction is caused by volitals, like H2O, CO2. These are carried down by the plate, mainly in the form of weak minerals. These minerals break down with pressure and temperature into stronger minerals that don't contain water and carbon dioxide. The leftover gases and liquids travel into the mantle (the mantle wedge) and hydrate the mantle, causing melting. The melt rises and then... volcano!

The other main cause is from rising mantle material, which forms decompression melting. Basically, hot mantle is kept from melting by the pressure of the earth at depth. When this material rises, the pressure drops much faster than the temperature, and thus it partially melts. This mainly occurs at divergent boundaries and hot spots, which are areas in plate tectonics that have rising materials or spreading.

Answer 2

Magma pockets below the Earth's crust begin to move their contents upwards usually due seismic activity (which is why volcanoes have associated earthquakes sometimes). As the magma moves up into a volcano, the magma, steam, and other gasses cause tremendous pressure. Eventually the magma and gasses erupt from the volcano, either through a previous opening or blows an opening out (like Mt. Saint Helens). Once the magma is on the surface it is called lava. Rocks and ashes that are thrown out are called pyroclastics.

Answer 3

A volcano arises from magma erupting through the crust due to a disruption in the mantle.

The upper mantle, called the asthenosphere is liquid and allows plates to move along the earth`s surface.

Volcanoes occur at plate boundaries (where plates move together or apart).
As plates move apart, magma rises through the crack formed in the crust, to fill this space, and thus causes low, disc shaped volcanoes.
Where plates move together, one plate is subducted underneath the other, and thus causing disruption in the mantle which causes magma to rise to the surface and erupt.

Viscous magma is high in silica and causes gases to be trapped in the magma chamber. Over time pressure builds up causing explosive volcanoes, which cause magma to shoot out of the vent.
Magma low in viscosity pours out quietly causing the summit to collapse into the chamber.

Answer 4

as magma enters the upper levels of the volcano the gas make the magma volatile and this causes the magma start to erupted,it is ways the volume of magma under the ground and it is also under a ex stream amount of pressure.this will cause the eruption.