Exploring Alaska's Undersea Volcanoes
NOTE: The following story is about research that occurred in 1999, when the deep-submergence vehicle Alvin conducted research in the Gulf of Alaska. The research was funded by the West Coast and Polar Regions Undersea Research Center at the University of Alaska Fairbanks. Alvin is tentatively scheduled to return to Alaska waters in 2002. More about Alvin's 2002 schedule...
INTRO: Just off the coast of Alaska's Kodiak Island, the North Pacific Ocean quite literally drops into an abyss more than 10,000 feet deep. Rising up from the ocean floor are undersea mountains, called seamounts. One of the oldest and biggest is Patton seamount. As Doug Schneider reports in this week's Arctic Science Journeys Radio, scientists used the submersible that found the Titanic to see the undersea mountain for the first time.
STORY: At over six feet tall, Randy Keller isn't the first person you'd expect to willingly cram himself into a seven-foot titanium sphere for a ten-hour journey to the ocean floor. But as a geologist with Oregon State University, he wasn't about to miss the chance to see one of Alaska's largest undersea mountains.
KELLER: "The first impression when you climb into the sub is just how incredibly small it is. It borders on claustrophobic. It's only about seven feet in diameter. About half of that is taken up by electronic gear—cameras, recorders and sensors—and so it's a very confining space. That's what you first notice, but almost instantly you're distracted by all of the incredible stuff that's going on around you. After about 30 seconds I didn't notice how small the space was anymore."
The submarine Keller was in is probably the world's most famous deep-sea submersible. Called Alvin by its handlers at the Woods Hole Oceanographic Institution, the submersible is built to withstand ocean pressures down to nearly 15,000 feet. Ever since it was built in 1964, scientists have used it to explore some of the deepest regions of the sea. In 1986, Alvin made history when it located the wreck of the Titanic ocean liner, lost in 1912 when it struck an iceberg off the coast of Newfoundland.
On this particular cruise, Keller is studying the geology of the Patton seamount, a 10,000-foot extinct volcano in the central Gulf of Alaska, about 200 miles southeast of Kodiak Island. Although there to learn how the volcano formed, he was amazed by the variety of creatures living on the seamount's slopes.
KELLER: "When you hit the bottom and they turn on the lights, it's just astonishing how much there is around you. You see rocky outcroppings and there's life everywhere—sponges and sea stars. You're just overwhelmed by how much there is to see and you're trying to take it all in. It's pitch black all the time and only a few degrees above freezing. It's under phenomenal pressure from the depth. And yet there's so much life that it's just amazing. And I'm not even a biologist."
Scientists believe that Patton and nearby undersea mountains got their start millions of years ago off the coast of what today is Oregon. As the massive Pacific plate slid over a particularly hot spot in the earth's core, Keller says magma bubbled up through the earth's crust and created the seamounts.
KELLER: "The theory is that it's a hot spot, a point source deep within the earth that is sending up a plume of lava or magma. And that's burning a hole through the tectonic plate as it moves around. So you end up with a conveyor-belt-like effect where the plate is moving along the surface and you get volcanic activity in one place at a time. You end up with this trail of volcanic seamounts that trail away from where the hot spot is. We think that's how the seamounts in the Gulf of Alaska formed because you can trace this trail of seamounts from where they are oldest up near Kodiak Island, and they get younger as you go toward where the hot spot is now, off the coast of Oregon.
At 30 million years old, the Patton seamount is the oldest in an arc some 200 miles long. The youngest, of course, is the seamount presently being formed over the hot spot off the Oregon coast. In between, seamounts date from 8 to about 20 million years old.
For colleague Robert Duncan, a marine geologist from Oregon State, a trip to the seamounts is a journey of discovery.
DUNCAN: "Being the first one, the first human being to have that view out the portal, that you were the first to see that patch of the ocean floor, to see that collection of rocks and animals is a thrill. Because the ocean is so vast and there are so few diving missions that every time we go to a new feature, we see things for the first time."
For those of us not lucky enough to score a ride on Alvin and see the Patton seamount for ourselves, Keller and Duncan have created a 3-D computer visualization that can be seen on the Internet.
DUNCAN: "It's an animated fly-through, as if we were able to remove all of the seawater and we're in a vehicle that allows us to fly down around the volcano and examine the volcanic spires and the faults and the cliffs from any orientation and any direction."
OUTRO: This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program and the University of Alaska Fairbanks. I'm Doug Schneider.
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Thanks to the following individuals for help preparing this script:
Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks.
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Patton seamount 3-D animation (28MB).
Life on the Patton Seamount 1 (11.8 MB)
Life on the Patton Seamount 1 2 (7.4 MB)
(Courtesy Oregon State University)
Topo maps (PDFs)
Just like mountains on land, undersea mountains can be mapped to show topographical features. These two topographical maps were made to show Patton seamount elevation changes.
(Courtesy Oregon State University)
Continuously operated by the Woods Hole Oceanographic Institution, the original Alvin deep-submergence vehicle went into service in 1964, and was designed to operate at depths to 6,000 feet. Although the vehicle itself has undergone many conversions and changes designed to extend its operating depth, the name Alvin has stood the test of time. During its 37 years, the submersible has made more than 3,800 dives. Today, Alvin is certified by the U.S. Navy to dive to 4,500 meters or 14,764 feet. That's nearly three miles beneath the ocean surface.
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