Seamount

A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface (sea level), and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from the seafloor to 1,000-4,000 metres (3,000-13,000 ft) in height. They are defined by oceanographers as independent features that rise to at least 1,000 metres (3,281 ft) above the seafloor. The peaks are often found hundreds to thousands of metres below the surface, and are therefore considered to be within the deep sea. There are an estimated 100,000 seamounts across the globe, with only a few having been studied. Seamounts come in all shapes and sizes, and follow a distinctive pattern of growth, activity, and death. In recent years, several active seamounts have been observed, for example Loihi in the Hawaiian Islands.