Data could help unlock mystery of undersea supervolcanoes

April 12th, 2010 - 3:36 pm ICT by IANS  

Washington, April 12 (IANS) Scientists drilling into a large volcanic mountain chain lying underwater off the coast of Japan have collected new data that may provide clues to unlocking the mystery of undersea supervolcanoes.
In 2009, they undertook the Integrated Ocean Drilling Program (IODP) Expedition 324, drilling five sites on the Pacific Ocean floor to study the origin of the 145 million-year-old Shatsky Rise volcanic mountain chain.

The data collected during the IODP expedition may provide vital clues.

Located 1,500 km east of Japan, Shatsky Rise is as big as California. This underwater chain represents one of the largest supervolcanoes in the world: the top of Shatsky Rise lies three-and-a-half kilometres below the sea surface, while its base plunges to nearly six kilometres below the surface.

“Seafloor supervolcanoes are characterised by the eruption of enormous volumes of lava,” says William Sager of Texas A&M University, who led the expedition with co-chief scientist Takashi Sano of Japan’s National Museum of Nature and Science in Tokyo.

“About a dozen supervolcanoes exist on earth - some are found on land, while others lie at the bottom of the ocean. Those found on the seafloor are often referred to as “large oceanic plateaus,” Sager adds.

Current scientific thinking suggests that these supervolcanoes were caused by eruptions occurring over a period of a few million years or less - rapid pace in geological time.

Each of these supervolcanoes produced several million cubic km of lava - about 300 times the volume of all the Great Lakes combined - dwarfing the volume of lava produced by the biggest present-day volcanoes such as Hawaii, says an IODP release.

The IODP Shatsky Rise expedition focused on deciphering the relationship between supervolcano formation and the boundaries of tectonic plates, which may prove crucial to understanding what triggers supervolcano formation.

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