<P> In geology, the places known as hotspots or hot spots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle . Their position on the Earth's surface is independent of tectonic plate boundaries . There are two hypotheses that attempt to explain their origins . One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core--mantle boundary . The other hypothesis is that lithospheric extension permits the passive rising of melt from shallow depths . This hypothesis considers the term "hotspot" to be a misnomer, asserting that the mantle source beneath them is, in fact, not anomalously hot at all . Well known examples include Hawaii, Iceland and Yellowstone hotspots . </P> <P> The origins of the concept of hotspots lie in the work of J. Tuzo Wilson, who postulated in 1963 that the formation of the Hawaiian Islands resulted from the slow movement of a tectonic plate across a hot region beneath the surface . It was later postulated that hotspots are fed by narrow streams of hot mantle rising from the Earth's core--mantle boundary in a structure called a mantle plume . Whether or not such mantle plumes exist is the subject of a major controversy in Earth science . Estimates for the number of hotspots postulated to be fed by mantle plumes has ranged from about 20 to several thousands, over the years, with most geologists considering a few tens to exist . Hawaii, Réunion, Yellowstone, Galápagos, and Iceland are some of the most active volcanic regions to which the hypothesis is applied . </P>

How is a volcano formed at a hotspot
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