In areas where the plates come together, sometimes volcanoes will form. Volcanoes can also form in the middle of a plate, where magma rises upward until it erupts on the sea floor, at what is called a hot spot.
Volcano's do make islands You have heard of Hawaii haven't you. Lava rises up from the floor of the sea building up until the cinder cone breaks the waves. Ocean action current and waves break the cone down and more volcanic action keeps building up wider each eruption.  Confidence votes 48. A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. 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. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to 1,000–4,000 metres (3,300–13,100 ft) in height. Most seamounts are volcanic in origin, and thus tend to be found on oceanic crust near mid-ocean ridges, mantle plumes, and island arcs. Overall, seamount and guyot coverage is greatest as a proportion of seafloor area in the North Pacific Ocean, equal to 4.39% of that ocean region. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, Iceland. Convergent plate boundaries Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. As the plate moves over a fixed spot deeper in the Earth where magma (molten lava) forms, a new volcano can punch through this plate and create an island. The Hawaiian Islands are believed to be formed from one such 'hot spot'. As the plate moves away, the volcano stops erupting and a new one is formed in its place. The Hawaiian Islands are volcanic in origin. Each island is made up of at least one primary volcano, although many islands are composites of more than one. The Big Island, for instance, is constructed of 5 major volcanoes: Kilauea, Mauna Loa, Mauna Kea, Hualalai and Kohala. Eruption of an Hawaiian Volcano. A volcanic island in the South Pacific Ocean is also the biggest mountain in the world. Mauna Loa, one of the volcanic islands that make up the big island of Hawaii, is the most massive single mountain in the world because of its sheer bulk. Each eruption of the sea floor volcano builds up the volcano a little bit higher. Until one day, the eruptions have built the top of the undersea mountain so high, that it rises above the ocean’s surface. Sometimes, volcanoes occur in close proximity to each other on the sea floor, creating a very large island. In areas where the plates come together, sometimes volcanoes will form. Volcanoes can also form in the middle of a plate, where magma rises upward until it erupts on the sea floor, at what is called a “hot spot.”. The Hawaiian Islands were formed by such a hot spot occurring in the middle of the Pacific Plate. While the hot spot itself is fixed, the plate is moving. So, as the plate moved over the hot spot, the string of islands that make up the Hawaiian Island chain were formed. The Hawaiian Islands form an archipelago that extends over a vast area of the North Pacific Ocean The Hawaiian Islands were formed by volcanic activity. The Hawaiian Emperor seamount chain is a well-known example of a large seamount and island chain created by hot-spot volcanism. Each island or submerged seamount in the chain is successively older toward the northwest. Volcanoes can also form in the middle of a plate, where magma rises upward until it erupts on the sea floor, at what is called a “hot spot.”. The Hawaiian Islands were formed by such a hot spot occurring in the middle of the Pacific Plate. While the hot spot itself is fixed, the plate is moving. Geography of the Sea: Volcanic Islands. Another type of mountain in the sea is an island. It rises from the sea floor, but reaches above the ocean’s surface, sometimes just barely. An island is a solitary mountain formed by volcanic activity. Lava erupting from the sea floor builds up on the sea bed over thousands, or even millions of years. The lava cools rapidly as it reaches the ocean water and forms solid rock. Each eruption of the sea floor volcano builds up the volcano a little bit higher. Until one day, the eruptions have built the top of the undersea mountain so high, that it rises above the ocean’s surface. Sometimes, volcanoes occur in close proximity to each other on the sea floor, creating a very large island.
https://answers.yahoo.com/question/index?qid=20060920174751AAFhwAh http://www.answers.com/Q/How_do_volcanoes_create_islands https://en.wikipedia.org/wiki/Seamount http://www.answers.com/Q/How_do_volcanoes_create_islands http://www.soest.hawaii.edu/GG/HCV/haw_formation.html http://www.extremescience.com/volcanic-islands.htm http://oceanservice.noaa.gov/facts/hawaii.html http://oceanservice.noaa.gov/facts/hawaii.html http://www.extremescience.com/volcanic-islands.htm
how does a seafloor volcano create an island