Submarine volcanoes or underwater volcanoes, come in all shapes and sizes and, are found across the world from Hawaii and California to Iceland, Japan, New Zealand and Antarctica. Worldwide, there are an estimated 5,000 active submerged volcanoes, with the highest volcanoes in shallow water rising above sea level. Most submerged volcanoes, however, are located on ocean ridges. Volcanoes are dangerous, but when compared to land volcanoes, submarine volcanoes pose less of a threat to human life. Since the volcano sits far below the ocean’s surface, even a major eruption may not be detected from above. Nonetheless, care must be taken when exploring areas surrounding a submarine volcano.
Since 1650, when the Kolumbo submarine volcano erupted, killing at least 70 people on the nearby Greek island of Santorini, submerged volcanoes have been known to be deadly. Submarine volcanoes, as the name suggests, are volcanoes that sit under water on the ocean floor. The biggest underwater volcano is in Hawaii, and if measured from sea floor, it is actually larger than Mount Everest (Loihi) Underwater volcanoes are formed as the surface of the Earth rips apart since the ocean surface is denser than the underlying mantle it creates pressure on the mantle and the surface cracks. When a submarine volcano erupts the result is different — and usually less dramatic — than the eruption of a land volcano. Unless the volcano breaks sea level, upon an eruption lava immediately comes into contact with ocean water. The water acts to cool the lava and to transform the lava into a solid state as rubble or sand.