One interesting fact about underwater volcanoes is that they deposit about 75 percent of the annual magma output on Earth. The molten magma and hardened lava shape the ocean floor and create the edges of the new plates on the ocean floor.
The largest underwater volcano is the Krakatau, a volcanic island between Sumatra and Java in Indonesia. It is mostly a submerged caldera, a basin-shaped volcanic depression formed from a previous powerful volcanic eruption. Located in the Sundra Strait, Krakatau is approximately 5.5 miles long and 3 miles wide.
Underwater or submarine volcanoes are commonly found in ocean ridges or areas where tectonic plates move away or towards each other. Because most of these volcanoes are submerged, they do not produce the same spectacular volcanic eruption like some of their terrestrial counterparts. Their constant activity, however, greatly transforms the majority of the oceanic crust.
It is also an interesting fact that the chain of islands in the Pacific, specifically the Hawaiian Islands, is formed through continuous volcanic eruptions. The Hawaiian hot spot, which sits near the Pacific Plate, is responsible for the formation of the Big Island in Hawaii. The largest island in the state is also home to five volcanoes, of which three are active. Other hot spots are found in other parts of the world, such as Galapagos Islands and Iceland.Learn More
The number of potential active volcanoes on Earth is estimated to be about 1500, with 550 of these having erupted in recorded history. The total number of volcanoes throughout the entire world is unknown, because not all volcanoes are accessible, known and recorded.Full Answer >
Volcanoes occur when magma is able to reach the surface of the Earth through a gap in the crust. This typically occurs at plate boundaries, where two tectonic plates pull away or move against each other. Volcanoes can also form at weak points in plates, called hot spots.Full Answer >
Cinder cone volcanoes form when high temperatures and pressure melt rock deep inside the Earth. Once a large amount of magma forms, it rises until it reaches the surface, creating an eruption.Full Answer >
Some facts about composite volcanoes include the fact that some of the best-known mountains around the world are composite volcanoes. This list includes Mount Fuji in Japan, Mount Hood in Oregon and Mount St. Helens and Mount Rainier in the state of Washington.Full Answer >