Why do volcanoes form at plate boundaries and hot spots?

Answer 1

because the plates under the earths crust are always moving some times the plates crash into each other this sometimes makes one plate sink under the other one and burning up, or pushing up on each other which makes mountains and volcano's.

Answer 2

There are two forms of plate boundary volcanism, the reasons for their formation differ in their processes.

One involves the subduction of oceanic crust in collisions between plates that are moving toward each other, whereby the introduction of cold, wet, oceanic rock into the hot asthenospheric rock causes some melt to occur. The melted rock, or magma, will try to rise toward the surface due to its buoyancy in relation to the host rock. When the rising molten rock reaches the surface, an eruption will occur, creating a volcano.

The other plate boundary volcanism is called rift volcanism, the result of plates that are moving away from each other. In this case, the weakness in the lithosphere created by the diverging plates allows the hot rock of the asthenosphere to undergo decompression melting as it is rising to fill the gap. It is in this type of volcanism that new crust is being created.

Some volcanoes do not form near any plate boundary, however, for reasons unrelated to subduction or rifting.

Answer 3

There are two mechanisms depending on the type of boundary. At divergent boundaries where plates move apart the crust is thin. This reduces pressure on the upper mantle, reducing the melting point and alowing some rock to melt. This molten material then rises to the surface to form volcanoes. At subduction zones, where one plate slides under another, the plate plunging into the mantle takes water with it. The water seeps into the mantle, lowering the melting point with similar results.

Answer 4

Everything on Earth's surface is on a tectonic plate. About 90% of volcanoes on Earth, however, are located near the boundaries where two of these plates meet. There were two mechanisms as to why this happens. Where an oceanic plate collides with a less dense oceanic or continental plate, it is force down into the mantle. taking some seawater with it. This water seeps into the superheated rocks of the mantle and lowers the melting point. The resulting molten rock, called magma, then rises to the surface to form volcanoes.

Where two plates are pulling apart the crust is thin. This reduces the pressure on the uppe part of the mantle, therefore lowering the melting point. This allows some of the rock to melt, rise up, and form volcanoes.

Answer 5

They often form on the edge of a continental plate. The reason is that the movements of continental plates to and from each other cause fault lines in the underlying layers of the Earth's crust at the edges where they tear apart (as in Iceland) or are forced together (as on the North and South American west coasts). These cracks in turn allow the lava underneath to come through and where it does, vulcanos result.

Answer 6

Volcanoes form where columns of hot rock called mantle plumes rise up through the mantle and crust

Answer 7

According to scientists, the volcanic landforms at divergent ocean plate boundaries are known as oceanic ridges.

Answer 8

The edges of the Pacific Ocean correspond approximately to the location of tectonic plate edges, which collide and cause volcanoes and earthquakes.