Scuba Geek

Researchers present video of volcano erupting 550 mtrs underwater May 25, 2006

Posted by Andy Carroll in : Trivia , trackback

I often have a look through Underwater Times for some interesting stuff and found an article today, regarding a team of scientists who have been watching volcanoes erupting at the bottom of the ocean, 550 metres deep, near the Mariana Islands northwest of Guam.

The researchers have now observed eruptive activity at the site during three separate visits over a period of more than two years, suggesting that these types of deep-sea volcanoes erupt chronically for longer periods than other undersea volcanoes located on the mid-ocean ridge. The eruptive activity they just observed at a volcano dubbed Northwest Rota-1 was explosive, but provided some of the closest observations ever of a volcano, thanks to the help of an underwater robot.

“We were forced to evacuate the remotely operated vehicle, ‘Jason II,’ several times to avoid getting it enveloped in volcanic clouds,” said Bill Chadwick, an Oregon State University volcanologist and one of the authors of the study. “But at other times, we could observe the eruption from only 10 feet away - something you could never do on land. So in some ways, we were able to see processes more clearly at the bottom of the ocean than we ever could on land. That was surprising.”

In their Nature article, the authors outline their 2004 discovery of an active crater on the south side of Rota’s summit they named “Brimstone Pit” that was discharging a “pulsating, opaque, yellowish smoky plume with characteristics unlike any known hydrothermal plumes.” The plume would fluctuate in volume and intensity, punctuated by explosions of sulfurous clouds.

The researchers also describe their return visit to the site in 2005, when Rota showered their ROV with volcanic “bombs,” globs of semi-molten sulfur and debris about 15 centimeters in size that shot out 50 meters above Brimstone Pit.

Apparently there is some life at these depths. Shrimp apparently eat dead fish which sink to the seafloor after being poisoned in the toxic cloud above the volcano. Sometimes you just have to wonder what an amazing place the oceans are.