Q:

What causes a volcano to form?

A:

Quick Answer

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.

Know More

Full Answer

Volcanoes typically form around three tectonic features. Plate boundaries are common spots for volcano formation, either divergent plate boundaries where two plates are separating or convergent boundaries where two plates collide. The resulting damage can produce weak spots in the plate, allowing magma to flow up from beneath. Divergent boundaries tend to produce shallow flows of lava and occur regularly on the ocean floor. Convergent boundaries produce thick, viscous lava that may not reach the surface and is responsible for many of the undersea mountain ranges on the planet.

Hot spots are areas where a tectonic plate is weakened, allowing an upwelling of magma from below. Since tectonic plates move over time, these hot spots can create a series of volcanoes, each going dormant when it moves away from the hot spot. The Hawaiian islands are believed to be a result of a moving hot spot underneath the Pacific that created a chain of islands and undersea mountains from Midway to the currently active volcano of Kilauea.

Learn more about Volcanoes

Related Questions

  • Q:

    What is a main vent in a volcano?

    A:

    The main vent of a volcano is the outlet chamber in the Earth's crust that allows hot magma to reach the surface. While secondary vents may form to alleviate the pressure caused by a magma chamber, the main vent is responsible for giving volcanoes their familiar cone shape.

    Full Answer >
    Filed Under:
  • Q:

    What causes a volcano?

    A:

    Volcanoes form when magma, a mixture of hot gas and molten rock, flows out of fissures in Earth's crust. The powerful eruption creates vents in the crust, and mountainous formations take shape above ground as molten rock spreads out in layers and gradually cools down. Each successive eruption occurs when more gas and magma accumulate in the vents, building pressure below the crust.

    Full Answer >
    Filed Under:
  • Q:

    Where do volcanoes form?

    A:

    Volcanoes can form anywhere the Earth's crust allows magma to reach the surface. Typically, this occurs around plate boundaries, either where plates are pulling apart or where one is forcing its way under another. Weak spots can also develop away from plate edges, creating magma vents called hot spots.

    Full Answer >
    Filed Under:
  • Q:

    What causes a volcano to erupt?

    A:

    A volcano erupts when the pressure of a subterranean pool of magma becomes great enough to crack the earth's crust. Whether the eruption results in a violent explosion or a slow seepage depends on several different factors, according to How Stuff Works.

    Full Answer >
    Filed Under:

Explore