The name for volcanoes forming at hot spots is seamount: these volcanoes form along ridges on sea floors, and may rise high above the sea's surface, creating islands. Seamounts span among the greatest distances of all landforms on Earth, according to National Geographic. They cover vast stretches of land, generally protruding upwards from ocean crusts, although they sometimes appear beneath continents too.
Hot spots around the world give rise to seamounts. These hot spots, experts say, number between 40 and 50. They appear in all oceans of the world, including the Indian and Atlantic Oceans. In the Indian Ocean, one of the most active hot spots is the Reunion hot spot, which exists beneath the Reunion island. In the Atlantic Ocean, the hot spot called the Icelandic hot spot, which forms beneath Iceland, is the largest.
Sometimes seamounts exist independently, but they also merge with one another, forming long chains. These chains typically form islands, which may rise above sea level. In the United States, the Hawaiian Islands form from seamounts. These islands, like many others, spawned from a single hot spot. The northwest movement of the hot spot through the Pacific Ocean ultimately created the Hawaiian Island chain. The islands forming Hawaii vary widely in age: the oldest date back nearly 6 million years, while the youngest remain less than 1 million years old.