Q:

How does a volcano form?

A:

Quick Answer

A volcano forms when a vent in the Earth's crust allows magma to well up from below. The magma fills a void underneath the surface, and when it builds up enough pressure, it bursts through to the surface. As the magma cools, it hardens into rock, and multiple eruptions may build up the mountainous form of a volcano.

Know More
How does a volcano form?
Credit: Photographer of Barcelona Moment Getty Images

Full Answer

The Earth's crust seems solid, but it is actually made up of 17 large, rigid plates floating over a hot, malleable sea of molten rock. When these plates collide or pull apart, they can allow this molten material, called magma, to make its way upward into the crust. If magma finds a particularly weak spot, it may burst through to the surface, creating a volcano. These can come about as the result of a slow accretion of cooling lava, or they can be the result of spectacular, pressurized explosions.

In some cases, a single vent may create multiple volcanoes. The Hawaiian Islands are the result of a tectonic plate passing over a particular hot spot in the mantle, and that hot spot has created several volcanic mountains in the sea floor. The chain of islands and mountains created by this vent extends as far as Midway, and Kilauea is the current site of the active volcano.


Is this answer helpful?

Similar Questions

  • Q:

    How is a volcano formed?

    A:

    A volcano forms when magma rises through weakened areas of the crust from a magma reservoir many miles deep within the earth, pushing itself up through a vent. This vent acts as a release valve for pressure building up below, and when the new volcano erupts, thousands or millions of pounds of ash and molten rock slowly accumulate, forming a volcanic mountain.

    Full Answer >
    Filed Under:
  • Q:

    What causes a volcano to form?

    A:

    A volcano forms when magma pushes up through the Earth's crust from below, depositing lava on the surface. This lava cools, creating volcanic rock. Over time, repeated eruptions of lava build a cone-shaped mountainous structure, producing a volcano.

    Full Answer >
    Filed Under:
  • Q:

    How does a volcano occur?

    A:

    Volcanoes occur when magma and heated gases from below the Earth's crust are channeled to the surface through fissures in the crust layer. Magma is molten rock that is called lava once it reaches the surface.

    Full Answer >
    Filed Under:

Explore