Philippine Island Arc system is formed due to subduction of Philippine Sea plate under the Sunda Plate (major continental shelf of the Eurasian plate). The trench formed here is called Philippine Trench. The Sunda Shelf and its islands is known as the Sundaland block of the Eurasian plate.

As a lithospheric slab is being subducted, the slab melts when the edges reach a depth which is sufficiently hot. Hot, remelted material from the subducting slab rises and leaks into the crust, forming a series of volcanoes. These volcanoes can make a chain of islands called an “island arc”.

Oceanic-oceanic Where two oceanic plates converge the denser crust subducts the other. This creates a trench. As the oceanic plate descends it melts, and the magma rises forming a volcanic island chain, known as an island arc.

subduction zone

Japan has been situated in the convergent plate boundary during long geohistorical ages. This means that the Japanese islands are built under the subduction tectonics. The oceanic plate consists of the oceanic crust and a part of the mantle beneath it.

For example, the Hawaiian Islands are an example of a linear chain of volcanoes in the middle of the Pacific Ocean that is not an island arc. Thus, the volcano is composed partly of melted basalt and partly of melted sediments, a combination that has the mineral composition of andesite rock.

The Northeastern Japan Arc, also Northeastern Honshū Arc, is an island arc on the Pacific Ring of Fire. The arc runs north to south along the Tōhoku region of Honshū, Japan. It is the result of the subduction of the Pacific Plate underneath the Okhotsk Plate at the Japan Trench.

The baby island bubbled from the ocean about 65 kilometres northwest of the capital Nuku’alofa, becoming the world’s youngest land mass. The South Pacific archipelago’s 177th island is basically made up of minuscule pieces of volcanic rock piled on top of each other.

Gondwanaland