Volcanoes are holes or vents in the Earth's crust, created when molten hot magma under the crust of the Earth is forced upward to the surface. Magma collects in a chamber beneath the crust, pressure builds up and forces it up through cracks or fissure and a conduit to the surface is created. Hot gases try to escape but are trapped in the magma. The surface of the Earth begins to bulge until the pressure can no longer be contained. Gases and fragments are released in a violent explosion called a volcanic eruption.
A volcano can erupt many times in its lifetime. The material released over many eruptions gradually b
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