1. Seamount: This is the most basic landform formed by an underwater volcano. A seamount is a mountain rising from the ocean floor that doesn't break the surface. They are formed by the accumulation of lava and ash from repeated eruptions.
2. Guyot: A guyot is a flat-topped seamount. These are formed when the top of a seamount is eroded by waves and currents after it rises above sea level.
3. Volcanic Island: If a volcano erupts enough lava and ash to reach the surface of the ocean, it can form an island. These islands can be very small or very large, depending on the size and activity of the volcano.
4. Atoll: An atoll is a ring-shaped coral reef that surrounds a lagoon. They are formed when a volcanic island slowly sinks beneath the waves, leaving a ring of coral around the former island.
5. Submarine Volcanic Ridge: These are long, narrow ridges on the ocean floor formed by chains of underwater volcanoes. These ridges can stretch for hundreds or even thousands of kilometers.
6. Pillow Lava: Pillow lava is a type of lava that forms underwater. As lava erupts, it cools quickly and forms rounded, pillow-shaped structures. These pillows can be found on the flanks of underwater volcanoes and can be a significant part of the sediment deposited.
7. Ash Deposits: Underwater volcanic eruptions can also release large amounts of ash. This ash can settle on the ocean floor and form layers of sediment that can build up over time.
The specific landform that is created will depend on the specific circumstances of the volcanic eruption.
