what causes volcanoes in the Pacific Ocean basin?It is called the ring of fire.
http://en.wikipedia.org/wiki/Pacific_Ring_of_Fire
The Pacific Ocean basin is known as the "Ring of Fire" because it is home to a large number of volcanoes. These volcanoes are formed due to the tectonic activity and the movement of the Earth's tectonic plates in the region.
Here's an explanation of how this happens:
1. Tectonic Plates: The Earth's crust is divided into large pieces called tectonic plates. There are several tectonic plates that interact with each other around the Pacific Ocean basin. The primary plates in this region are the Pacific Plate, the North American Plate, the Eurasian Plate, and the Philippine Sea Plate.
2. Plate Boundaries: The areas where these tectonic plates meet are called plate boundaries. There are three types of plate boundaries: divergent, convergent, and transform.
3. Convergent Boundaries: The most common type of plate boundary found in the Pacific Ocean basin is the convergent boundary. At these boundaries, two tectonic plates collide with each other. There are three types of convergent boundaries:
a. Subduction Zones: When an oceanic plate collides with a continental plate, the denser oceanic plate is forced beneath the lighter continental plate in a process called subduction. As the oceanic plate sinks deeper into the Earth's mantle, it starts to melt due to the high temperatures and pressures, forming a magma chamber.
b. Island Arcs: The melting of the subducted oceanic plate leads to the production of magma. This magma is less dense than the surrounding rock, causing it to rise towards the Earth's surface. As it reaches the surface, it forms a series of volcanoes known as an island arc.
c. Continental Volcanic Arcs: When two continental plates collide, neither subducts beneath the other. Instead, the intense collision and compression cause the rocks to fold and buckle upwards, forming mountain ranges. In some cases, this process can also lead to the formation of volcanic activity.
4. Resulting Volcanoes: As a result of subduction or continental collisions at these plate boundaries, volcanoes form along the Ring of Fire in the Pacific Ocean basin. These volcanoes can be found on land in countries such as Japan, Indonesia, the Philippines, and along the western coast of the United States, as well as underwater along the Pacific Ocean floor.
So, the main cause of volcanoes in the Pacific Ocean basin (Ring of Fire) is the tectonic activity at convergent plate boundaries, where subduction or continental collisions occur.