The melted rock, known as magma, often pushes through cracks in the crust to form volcanoes. Hot spot volcanism is unique because it does not occur at the boundaries of Earth’s tectonic plates, where all other volcanism occurs. Instead it occurs at abnormally hot centers known as mantle plumes.

Does volcanism occur at hotspots?

The melted rock, known as magma, often pushes through cracks in the crust to form volcanoes. Hot spot volcanism is unique because it does not occur at the boundaries of Earth’s tectonic plates, where all other volcanism occurs. Instead it occurs at abnormally hot centers known as mantle plumes.

What happens at volcanic hotspots?

A volcanic “hotspot” is an area in the mantle from which heat rises as a thermal plume from deep in the Earth. High heat and lower pressure at the base of the lithosphere (tectonic plate) facilitates melting of the rock. This melt, called magma, rises through cracks and erupts to form volcanoes.

Where does hotspot volcanism most commonly occur?

northwest Pacific Ocean
The Hawaiian Islands and the chain of seamounts that continue their trend for about 6,000 kilometers (3,750 miles) into the northwest Pacific Ocean are an example of a hotspot track. The Island of Hawaii is the youngest, and most active, volcano in the chain.

What volcanoes form at hotspots?

Most hotspot volcanoes are basaltic (e.g., Hawaii, Tahiti). As a result, they are less explosive than subduction zone volcanoes, in which water is trapped under the overriding plate. Where hotspots occur in continental regions, basaltic magma rises through the continental crust, which melts to form rhyolites.

How do hotspots support the theory of plate tectonics?

The heat that fuels the hot spot comes from very deep in the planet. This heat causes the mantle in that region to melt. The molten magma rises up and breaks through the crust to form a volcano. While the hot spot stays in one place, rooted to its deep source of heat, the tectonic plate is slowly moving above it.

Are hotspots stationary?

Hotspots are almost stationary features in the mantle. There is evidence that hotspots can drift extremely slowly in the mantle, but hotspots are essentially stationary relative to the faster-moving tectonic plates. As a tectonic plate moves over a mantle hotspot, a chain of volcanoes is produced.

What is the hotspot theory?

A frequently-used hypothesis suggests that hotspots form over exceptionally hot regions in the mantle, which is the hot, flowing layer of the Earth beneath the crust. Mantle rock in those extra-hot regions is more buoyant than the surrounding rocks, so it rises through the mantle and crust to erupt at the surface.

How do hotspots predict plate movement?

Although most hot spots occur far from plate boundaries, they offer a way to measure plate movement. This is because a hot spot generally stays in one place while the tectonic plate above it keeps moving. At a hot spot, the heat from the plume partly melts some of the rock in the tectonic plate above it.

Why are hotspot volcanoes basaltic?

Most hotspot volcanoes are basaltic because they erupt through oceanic lithosphere (such as Hawaii, Tahiti). As a result, they are less explosive than subduction zone volcanoes, in which water is trapped under the overriding plate.

How is a hotspot volcano formed?

These so-called “hotspot” volcanoes are created when a narrow stream of hot mantle rises up from deep inside the earth and melts a hole in the plate so that the magma can ooze upward. The Hawaiian islands, for example, are a result of hotspot volcano formations near the center of the giant Pacific plate.

Where do hotspots occur in a tectonic plate?

Hotspots are associated with volcanic activity at the mid-ocean ridges, underwater boundaries between the tectonic plates of the earth’s crust. These are where “strike-slip” (horizontal motion) earthquakes occur. … Other hotspots occur at subduction zones, where one plate plunges into the earth beneath another.

How does subduction trigger volcanism?

Thick layers of sediment may accumulate in the trench, and these and the subducting plate rocks contain water that subduction transports to depth, which at higher temperatures and pressures enables melting to occur and ‘magmas’ to form. The hot buoyant magma rises up to the surface, forming chains of volcanoes.

What is the difference between a hotspot and a volcano?

Hawaii Volcanoes National Park. NPS photo. Introduction Some chains of volcanoes lie within the interiors of tectonic plates rather than along the edges. The volcanoes are progressively older away from the largest and most active volcano. A hotspot is a large plume of hot mantle material rising from deep within the Earth.

What causes hot spot volcanoes to form?

The melted rock, known as magma, often pushes through cracks in the crust to form volcano es. Hot spot volcanism is unique because it does not occur at the boundaries of Earth’s tectonic plate s, where all other volcanism occurs.

What is a hotspot in geography?

A hotspot is a large plume of hot mantle material rising from deep within the Earth. A line of volcanoes develops as a plate moves over a hotspot, much as a line of melted wax forms as a sheet of waxed paper is moved slowly over a burning candle.

Where do hot spots form?

These features are called diapir s. Scientists have different theories about where hot spots form. The dominant theory, framed by Canadian geophysicist J. Tuzo Wilson in 1963, states that hot spot volcanoes are created by exceptionally hot areas fixed deep below the Earth’s mantle.