Why Do Volcanoes Happen, And How Do They Work?

Question

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Answer 1

Volcanoes occur due to an upwelling of magma from the Earth's mantle. This can happen in a few different ways. For example some upwellings are just hot spots that are in one area of the mantle and have their source from large convection currents that remain stationary (like the one that formed the Hawaiian Islands).

Other volcanoes are associated with boundaries in the plates that make up the Earth's crust. For example the west coasts of both North and South America are lined by volcanoes because the ocean plates are being subducted under the Continental plates. As this occurs the ocean plates dive into the mantle, melt, and that newly melted crust "bubbles" to the surface in eruptions that form the Andes and Cascades.

The largest volcanic mountain range in the world covers the floor of the oceans like stitches on a baseball. The example you might be familiar with is the Mid-Atlantic Ridge. This ridge is a chain of volcanoes that are being formed by 2 plates slowly moving apart and magma rising to the surface forming new ocean floor.

Answer 2

A volcano is a rupture in the earth's surface or crust, allowing hot, usually molten rock, ash, and gases originating deep below the surface to periodically escape. Volcanic activity involving the extrusion of rock tends to form mountains or mountain-like features over time.

Volcanoes are generally found where two to three tectonic plates diverge or converge. The mid-oceanic ridges, like the Mid-Atlantic Ridge, are typical examples of divergent tectonic plates where volcanoes are formed, whereas the Pacific Ring of Fire is a typical example of volcanic activity on convergent tectonic plates. Where two tectonic plates slide past one another (like the San Andreas fault) volcanic activity is generally not found.

Volcanic activity can also occur from mantle plumes, the so-called hotspots, which occur at locations far from plate boundaries; hotspot volcanoes are also found elsewhere in the solar system, especially on its rocky planets and moons.

Answer 3

volcanoes occur when the molten lava from the earth's core explode onto the open spot due to the movents of the earth's plate and such. volcanoes can be anywhere, ranging from mountains to ocean floors, but they always start out flat. over time, volcanoes form mountains and islands. Hawaii is a god example of that.

Answer 4

The generally accepted theory is that there is an upward circulating current of hot magma deep underground that melts the rock above it at one point, and molten magma leaks out, melting the surface rocks into lava. The rock expands as it heats up, so it causes pressure underneath the surface.

26 OCT 06 2341 hrs