It could be land masses that were already there, it doesn't always have to volcano made. Or, It could be land that was under ground that was exposed when water levels went down
An earthquake made a volcano erupt which made hawaii. Tajeem
Sheild volcanos
the Bahamas are make of many under water volcano's
An underwater volcano. The volcano that made Hawaii was a shield volcano.
Volcano Islands are the remains of dormant or still active volcanoes that have formed islands of land above the surface of the sea.
The Hawaiian islands are made up of many volcanoes, most of which are extinct. However, one volcano, Kilauea on the big island, is one of the most active volcanoes in the world.
The canary islands are all sitting on the top of an underwater volcano that has been dormant for hundreds of years. I also know that most of the individual islands have there own volcano's and on tenerife it is due to erupt soon as it does every 100 years. So the islands are on the top of a volcano with a volcano on top of most of them.
Hawaii
phillipines
abridoa normal
the Cayman Islands were formed from an eruption of an underwater volcano.
under the sea , on islands