Marine scientists discover deepest undersea erupting volcano

Scientists funded by the National Science Foundation (NSF) and NOAA have recorded the deepest erupting volcano yet discovered--West Mata Volcano--describing high-definition video of the undersea eruption as "spectacular."

"For the first time we have been able to examine, up close, the way ocean islands and submarine volcanoes are born," said Barbara Ransom, program director in NSF's Division of Ocean Sciences. "The unusual primitive compositions of the West Mata eruption lavas have much to tell us."

The volcanic eruption, discovered in May, is nearly 4,000 feet below the surface of the Pacific Ocean, in an area bounded by Fiji, Tonga and Samoa.

"We found a type of lava never before seen erupting from an active volcano, and for the first time observed molten lava flowing across the deep-ocean seafloor," said the expedition's chief scientist Joseph Resing, a chemical oceanographer at the University of Washington.

"It was an underwater Fourth of July, a spectacular display of fireworks nearly 4,000 feet deep," said co-chief scientist Bob Embley, a marine geologist at NOAA's Pacific Marine Environmental Laboratory in Newport, Ore.

"Since the water pressure at that depth suppresses the violence of the volcano's explosions, we could get an underwater robot within feet of the active eruption. On land, or even in shallow water, you could never hope to get that close and see such great detail."

Imagery includes large molten lava bubbles three feet across bursting into cold seawater, glowing red vents exploding lava into the sea, and the first-observed advance of lava flows across the deep-ocean floor.

Sounds of the eruption were recorded by a hydrophone and later matched with the video footage.

Expedition scientists released the video and discussed their observations at a Dec. 17 news conference at the American Geophysical Union (AGU)'s annual fall meeting in San Francisco.

The West Mata Volcano is producing boninite lavas, believed to be among the hottest on Earth in modern times, and a type seen before only on extinct volcanoes more than one million years old.

University of Hawaii geochemist Ken Rubin believes that the active boninite eruption provides a unique opportunity to study magma formation at volcanoes, and to learn more about how Earth recycles material where one tectonic plate is subducted under another.

Water from the volcano is very acidic, with some samples collected directly above the eruption, the scientists said, as acidic as battery acid or stomach acid.  ...

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