Why in the News?

Recently a new island emerged near Japan's Ogasawara island chain after an undersea volcano erupted.

What is Phreatomagmatic Eruption?

• A phreatomagmatic eruption is a volcanic eruption caused by the interaction of magma and water.
• They differ exclusively from magmatic and phreatic eruptions.
• Unlike phreatic eruptions, the products of phreatomagmatic eruptions contain juvenile (magmatic) debris.
• Large explosive eruptions typically contain magmatic and phreatomagmatic components.
• Phreatomagmatic ash is formed by the same mechanism over a wide range of basic and acidic compositions.
• A blocky and uniform crust with low vesicle content is formed.
• Deposits from phreatomagmatic eruptions are thought to be better classified and finer-grained than those from magmatic eruptions.
• This is the result of higher fragmentation of phreatomagmatic eruptions.

About Ogasawara Islands:

• The Ogasawara Islands are a group of more than 30 small subtropical islands in the North-Western Pacific Ocean roughly 1,000 km south of the main Japanese Archipelago.
• It is also known as the Bonin Islands.
• It is one of the famous UNESCO World Heritage sites of Japan.