Why would a volcanoe form near a subduction zone?

Question

Studying plate tectonics.

Answer 1

When one plate is forced under another at a subduction zone, the rock in that plate begins to melt. Magma from the melted rock is lighter than the solid rock around it and begins to rise. Any crack in the plate above the magma will allow the magma to move toward the surface and form a volcano.

Answer 2

Subduction zones mark sites of convective downwelling of the Earth's lithosphere (the crust plus the strong portion of the upper mantle). Subduction zones exist at convergent plate boundaries where one plate of oceanic lithosphere converges with another plate and sinks below into the mantle. It is at subduction zones that the Earth's lithosphere, oceanic crust, sedimentary layers, and trapped water are recycled into the deep mantle. Earth is the only planet where subduction is known to occur; neither Venus nor Mars have subduction zones. Without subduction, plate tectonics could not exist and Earth would be a very different planet: Earth's crust would not have differentiated into continents and oceans and all of the solid Earth would lie beneath a global ocean.

When an old, hard edge of an oceanic plate slides into and underneath a more buoyant continental plate, the wet oceanic plate sinks into the mantle, its absorbed water rising into the overlying mantle. This water causes the overlying mantle to melt to form magma. Bubbles of sulphur dioxide, water vapour and carbon dioxide rise with the magma, growing in size as they approach the Earth's surface. Like a can of pop shaken too hard, the gases want out. When that happens, we have a VOLCANIC ERUPTION. The more gas there is, the faster it will force its way out, and the more likely it will explode when it gets to the surface.

A small number of volcanic eruptions occur not at plate boundaries but in the middle of one. It is believed that there are "hot spots" around the world where magma, less dense than the surrounding rock, rises up through structurally weak zones and bursts through a tectonic plate. As the plate moves, bursts of magma create a string of volcanoes. This creates a volcanic chain such as the Hawaiian Islands.

Answer 3

At a subduction zone there will two plates coming together, one continental plate composed of mostly granite and one ocean plate composed mostly of basalt. Upon colliding, the basalt ocean plate will move underneath the granite continental plate. As it moves lower and into the Earth's mantle, it will melt. This means that there is a large amount of pressure and heat from the newly formed magma. The magma will be pushed away from the Earth's core and can rise to the surface of the Earth's crust.

Answer 4

yup....plate melts on its way 2 the mantle than rises cuz it's hot....creating a magma chamber then a volcano.