Question

A volcanic island arc is the result of ________. subduction of continental crust underneath continental crust subduction of oceanic crust underneath continental crust subduction of oceanic crust underneath oceanic crust subduction of continental crust underneath oceanic crust

Answer 1

A volcanic island arc forms when the oceanic crust subducts beneath other oceanic crusts, creating volcanoes in a linear belt along the subduction zone. This process is part of the greater cycle of plate tectonics that balances crust formation and destruction.

Step-by-step explanation:

A volcanic island arc is the result of the subduction of the oceanic crust underneath the oceanic crust. This process involves one tectonic plate with oceanic crust being forced below another plate, also with oceanic crust, leading to a subduction zone. The subducted plate then descends into the mantle where it experiences high pressure and temperature, eventually melting and giving rise to magma. This magma can then rise to the surface, forming a volcanic arc, as seen with the Japan trench along the coast of Asia.

Subduction zones not only produce volcanic arcs but also drive the cycle of plate tectonics by balancing the formation of new crust at rift zones with the destruction of old crust. In addition, back-arc basins may form as a result of extension caused by mantle convection behind a subduction zone and its island arc.

Answer 2

At convergent boundaries, tectonic plates collide with each other. The events that occur at these boundaries are linked to the types of plates — oceanic or continental — that are interacting.

Subduction Zones and Volcanoes

At some convergent boundaries, an oceanic plate collides with a continental plate. Oceanic crust tends to be denser and thinner than continental crust, so the denser oceanic crust gets bent and pulled under, or subducted, beneath the lighter and thicker continental crust. This forms what is called a subduction zone. As the oceanic crust sinks, a deep oceanic trench, or valley, is formed at the edge of the continent. The crust continues to be forced deeper into the earth, where high heat and pressure cause trapped water and other gasses to be released from it. This, in turn, makes the base of the crust melt, forming magma

The magma formed at a subduction zone rises up toward the earth's surface and builds up in magma chambers, where it feeds and creates volcanoes on the overriding plate. When this magma finds its way to the surface through a vent in the crust, the volcano erupts, expelling lava and ash. An example of this is the band of active volcanoes that encircle the Pacific Ocean, often referred to as the Ring of Fire.A subduction zone is also generated when two oceanic plates collide — the older plate is forced under the younger one — and it leads to the formation of chains of volcanic islands known as island arcs. Examples include the Mariana Islands in the western Pacific Ocean and the Aleutian Islands, off the cSince the collision and subduction of plates is not a smooth process, large, powerful earthquakes are another phenomenon that result from this type of interaction. Earthquakes generated in a subduction zone can also give rise to tsunamis. A tsunami is a huge ocean wave caused by a sudden shift on the ocean floor, such as an undersea earthquake. If the wave reaches land, it can cause incredible destruction, like the Asian Tsunami, which killed more than 200,000 people in 11 countries across the Indian Ocean region in December 2004.oast of Alaska.