Hotspot volcanism

Hotspot volcanism is volcanic activity caused by anomalously hot mantle rising beneath a tectonic plate, often far from plate boundaries. As the plate moves over a relatively stationary source, it can form a chain of volcanoes.

Mantle plume: A buoyant upwelling of unusually hot mantle that can rise from deep within Earth. A plume is the proposed long-lived heat source beneath many hotspots.
Hawaiian–Emperor seamount chain: A submarine and island chain extending from Hawaii toward the Aleutian Trench. Its age pattern and bend are classic evidence used to infer Pacific Plate motion.
J. Tuzo Wilson: A Canadian geophysicist whose work helped establish plate tectonics and the hotspot explanation for island chains. Wilson proposed that stationary volcanic sources could create chains as plates moved over them.
Subduction zone volcanism: Volcanism above a descending tectonic plate, commonly driven by water released into the mantle wedge. It is boundary-related volcanism, unlike the intraplate setting typical of hotspots.
Mantle plume hypothesis: The hypothesis that narrow upwellings from deep mantle regions produce many hotspots. It explains many hotspot tracks, but plume depth and prevalence remain disputed.
Decompression melting: Melting that occurs when rising rock experiences lower pressure without losing much heat. Upwelling mantle can melt as pressure falls beneath a hotspot.
Hawaii: A volcanic island group in the central Pacific formed above the Hawaiian hotspot. The active end of the chain shows hotspot volcanism occurring far from a plate boundary.
Plate tectonics: The theory that Earth’s lithosphere is divided into moving plates whose interactions shape its surface. Hotspot tracks became a way to measure plate motion away from plate boundaries.
Mid-ocean ridge volcanism: Volcanism at divergent plate boundaries where mantle rises and forms new oceanic crust. Both involve rising mantle, but ridge volcanism follows a plate boundary rather than a localized hotspot.
Seismic tomography: A method that uses seismic waves to reconstruct three-dimensional variations inside Earth. It can reveal low-velocity structures interpreted as hot mantle beneath hotspots.

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