New Area of Exploration Surfaces From the Santa Barbara Channel
Can a burp from the Earth sink a ship?
Some scientists believe so, suggesting that explosive releases of methane from the sea floor could explain the so-called Bermuda Triangle, where scores of ships and planes are said to have disappeared in the Western Atlantic.
The discovery of a sunken trawler near craters in the North Sea fed speculation last year that a British version of the baffling phenomenon had been found.
Now, the mapping of a series of pits and craters in the Santa Barbara Channel, along with an island that vanished ages ago, is energizing scientists at UC Santa Barbara.
“It’s very exciting,” said James Kennett, a marine geologist at the university. “We have evidence of major expulsions of methane gas in the past.”
Though an extremely remote possibility, a blowout could theoretically create a giant methane bubble, displacing the water under a passing ship and dropping the vessel beneath the resulting wake.
Sonar images of the sea bottom do not reveal any rusting hulks near the craters off California’s coast. And Edward Keller, a professor of geological sciences involved in the research, was at pains to discourage any talk about a California Triangle. “I’ll have every kook from Florida to Los Angeles calling me,” he said.
Nonetheless, the detailed images of the lumpy sea floor off Santa Barbara and Ventura counties’ coast reveal the presence of a dozen large craters that could be the remnants of ice age blowouts of methane, Keller said.
Measurements from an unmanned submersible craft sent to the craters nearly 1,000 feet below the surface showed that methane is still leaking from at least one.
Understanding the methane releases has meaning beyond the highly speculative possibility that, say, an oil tanker plying Santa Barbara’s shipping lanes could be sunk. Kennett is writing a book that raises the possibility that oscillating releases of methane could play a role in climate change.
“It could punch the climate into warming,” he said.
The craters were revealed by sonar maps of the channel created in 1998 by the Monterey Bay Aquatic Research Institute, which has been involved in research on the sea floor off the California coast.
Evidence of a Submerged Island
Along with the craters, the images reveal what Keller calls a drowned sibling of the Channel Islands chain. Keller said the island--which he has named Calafia for a mythical warrior queen who ruled a utopian empire--is about halfway between Santa Barbara and Santa Cruz Island.
Its significance, beyond the curiosity factor, is that it could help explain the remains of ancient mammoths found on the Channel Islands.
Keller suggested that the mammoths could have rested on Calafia while swimming out to what today are four islands in the Santa Barbara Channel: San Miguel, Santa Rosa, Santa Cruz and Anacapa. In the late Pleistocene Epoch 18,000 years ago, the Channel Islands were one giant offshore land mass that geologists refer to as “Santa Rosae.”
Elephants today are known to swim long distances for food. In the ice age, the future Channel Islands would have resembled Northern California, covered by thick greenery that would have been attractive to mammoths, said Keller.
Any mammoths heaving themselves up on the since-vanished island would have found a relatively flat land mass about 1.25 miles long. Today, the island lies under 300 feet of water.
Keller admits that he can’t be “1,000% sure” the land ever broke the surface of the sea. But he said all the indications are there. Unlike most underwater formations, which are smoothed out over the eons by the constant motion of the water, Calafia stands out in pictures as a roughly etched mound of cottage cheese-like rock.
There are also many shoreline-type features.
“The island shows signs of coastal erosion, had sea cliffs that were 30 feet high and was flat,” Keller said.
The ice age sea level was nearly 400 feet lower than it is today, he said, which meant the island would have been above the water at its highest point.
Keller will present his team’s findings to the Geological Society of America meeting in Boston on Nov. 4-5.
An expert in underwater seismic activity, Keller was originally more interested in the images of two offshore faults that straddle the island. One of them is capable of producing an earthquake of 7.5 magnitude, he said. The crest between the two colliding plates on which the island sits is slowly rising. In a few hundred thousand years, Calafia may thrust its nose out of the sea.
The crest, called an anticline in geologic terms, is about 30 miles long. In the east, it rises from the ocean floor and becomes South Mountain near Ventura. Ventura County mammoths would have had an easier time reaching Santa Rosae than the animals’ Santa Barbara cousins, because the offshore land mass was closer to shore there.
The craters can be more than 500 yards across.
“To make a pit that big, [the release of gas] must be pretty fast,” Keller said.
When it occurred 11,000 years ago, it would have produced a giant bubble bursting from the ocean similar to what occurs when someone gets a drink at the water cooler and air bubbles erupt from the bottom of the bottle.
100-Foot Domes Could Be Unexploded Gas Pockets
Though there were no ships cruising the seas then, any future eruption could endanger a modern vessel. “As gas comes up, buoyancy is lost,” Keller explained. “Imagine the water turning to gas. The boat falls in the hole. That would cause rapid sinking.”
Keller described other features nearby that resemble “geodetic domes,” about 100 feet high and about the same size as the craters. Perhaps, he said, they could be pockets of gas that have not yet escaped.
“It might be swelling, filling full of gas,” Keller said.
Marine geologist Kennett plans to return to the area early next year with a submersible to take more core samples for analysis.
The vanished island “could be a treasure house of fossils,” Keller said.
The research, which has cost several hundred thousand dollars, was funded by the Southern California Earthquake Center, the U.S. Geological Survey and the National Science Foundation.
