Plate tectonics is the main process that produces volcanoes, at subduction, convergent, and divergent zones. Yet, we see volcanic activity without the plate tectonics. "Hotspots" are found around the world. Many people who hear of the term hotspots, think of volcanoes and then the association of Hawaii, since it is a very common known hotspot. The Glossary of Geology (1987) defines "hotspots" as "a volcanic center, 100 to 200 km across and persistent for at least a few tens of millions of years, that is thought to be the surface expression of a persistent rising plume of hot mantle material. "Hotspots" are not linked with arcs, and may or may not be associated with oceanic ridges." "hotspots" are formed in the ocean by producing basaltic magma sources in the oceanic crust (Hawaiian Islands) and under continents where they produce granitic magma sources in the continental crust (Yellowstone). The concept of "hotspots" was studied by Wilson, Morgan, and Crough, "[A]s a broader swelling of topography capped by volcanism, which, combined with plate motion, generates volcanoes aligned in a chain and monotonic age progression" (Ito, Keken, 2007, p.2). The origin of hotspots continues to be a very controversial topic, since most of the evidence found does not apply to all known hotspots. This suggests that there may be more than one possible source of the hotspot formation and how they behave. .
History of Discovery and Different Theories.
Wilson, a Canadian Geophysicist, was one of the pioneers in the "hotspot" theory. He observed locations around the world, such as Hawaii, where there was active volcanic behavior. As previously mentioned, Wilson was one of the first to observe the process occurring around the world. He noted that there was volcanic activity creating island chains for long periods of time. In his paper, "A possible Origin of Hawaiian Islands," 1963 he articulated that small, long lasting and very hot regions called "hotspots" were located below the plates and thus supply localized sources of high thermal energy to sustain the ongoing volcanism.