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Volcanoes

Hot-spot volcanoes

The Hawaiian hot spotThe Hawaiian hot spot Many volcanoes form near the edges of tectonic plates—but not all of them. Hot-spot volcanoes are found above mantle plumes, areas beneath the Earth's crust where magma from the mantle wells up. In some places, often far from the plate edges, the magma forces its way through cracks in the crust and erupts on to the ocean floor or in the centre of continents. These are called "hot spots". After repeated eruptions, some undersea volcanoes may grow tall enough for their summits to break the surface of the water and so form islands. Thousands of Pacific Ocean islands have formed in this way. As the tectonic plate drifts over the hot spot, the volcanoes cool, cease erupting and become extinct. They eventually sink beneath the water's surface.


Hawaii or Hawaii or "Big Island"

Hawaiian Islands

The Hawaiian Islands are a good example of hot-spot volcanoes. They are all the tops of enormous volcanoes. The Pacific plate has been drifting for millions of years. As it moves, it carries the volcanic islands away from their hot spots. In time, a new volcanic island is created, then another, and so on. Eventually, a chain of volcanic islands is created. Some islands are several millions of years older than those at the southeastern end of the chain that still lie over the hot spot and where the volcanoes are still active.

More than 80 undersea volcanoes, the Emperor Seamounts, lie to the northwest of the Hawaiian islands, forming a continuous hot-spot volcano chain that stretches over 5800 kilometres (3600 miles), almost as far as the Kamchatka Peninsula in Russia.The Pacific Ocean floorThe Pacific Ocean floor

More than 80 undersea volcanoes, the Emperor Seamounts, lie to the northwest of the Hawaiian islands, forming a continuous hot-spot volcano chain that stretches over 5800 km (3600 miles), almost as far as the Kamchatka Peninsula in Russia.

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