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Apr 25 2020

Underwater volcano




Underwater volcano-Underwater volcano
Underwater volcano Geologists have identified more than 5,000 active underwater volcanoes, which account for more than 75% of the total lava that erupts every year. Most of these are located



Underwater volcano

Geologists have identified more than 5,000 active underwater volcanoes, which account for more than 75% of the total lava that erupts every year. Most of these are located along the mid-ocean ridges, where the Earth’s tectonic plates are spreading apart. Most of these are very deep underwater, and difficult to study, but some are located in more shallow water.

An underwater volcano erupts differently than a surface volcano. This is because there is an unlimited amount of water to cool down the lava. A shell of rock hardens around the lava almost immediately, creating a type of formation called pillow lava. Deeper than about 2,000 meters, the pressure of the water is so high that it can’t boil, and so underwater volcanoes are difficult to find using hydrophones.

Underwater volcanoes build up over time, and can eventually reach the surface of the ocean. This is what happened to form the Hawaiian islands. The Earth’s crust has drifted above an active vent, creating each of the islands in turn. A new Hawaiian island, Lo’ihi, is forming under the ocean about 48 km off the southeast coast of Hawaii. It’s already taller than Mount St. Helens and will breech the surface in a few hundred thousand years.

V olcanoes beneath the Sea:

Last May, amazed scientists watched as lava and ash blasted through the surface of the Pacific Ocean and high into the air. They were getting a rare glimpse of a live eruption from an undersea volcano. How do these submarine volcanoes work?

“Fiery birth of a new Pacific island read the May 24 announcement from the Australian Commonwealth Scientific and Industrial Organization (CSIRO). CSIRO had sent a team of researchers to study the dormant undersea Kavachi volcano in the Solomon Islands east of Australia.

They discovered that the volcano was not dormant at all. Molten magma and ash were shooting more than 200 feet into the air, while plumes of steam and smoke rose thousands of feet above the ocean’s surface.

Over the years, the material coming out of Kavachi had built up from the ocean floor, eventually rising over 3,000 feet until it broke through the water’s surface and formed a small island. “We arrived to find waves breaking on the volcanic peak. Violent eruptions were taking place very five minutes,” reported Brent McInnes, the expedition’s chief scientist.

Kavachi belongs to the world of submarine volcanoes, which mostly do their erupting out of sight and occasionally form islands above the surface of the water. In the case of Kavachi, these “ephemeral islands” have formed at least 8 times in the past 60 years, only to recede under the water. These islands have reached more than 500 feet in length.

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Underwater volcano

SOURCE: http://sites.google.com/site/volcanoesskills/what-is-a-volcano/what-is-a-volcano-1/underwater-volcanoes


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