Fact Sheet. Seamounts are underwater volcanoes found in every ocean. They can form in different ways, but most are remnants of extinct volcanoes. Seamounts are generally found at mid-tectonic plate regions, called hotspots, and near the boundaries of tectonic plates. Volcanic hotspots are areas of the Earth’s mantle from which hot plumes rise upward, forming volcanoes on the overlying crust (tectonic plates). As the volcanoes become extinct, this process can produce island chains and seamounts. Seamounts can also form at tectonic plate boundaries from eruptions at subduction zones and successive eruptions at seafloor spreading centers. This resource provides students with detailed information about the formation and geologic life cycle of seamounts. Download the PDF for the full version of this Fact Sheet.