Experts on red alert for mega-earthquake off the US coast

Scientists have a worry that a gap in the Pacific's 600-mile-long fault line could set off a devastating earthquake that would completely destroy communities in the northwest US.

On the edge of the dipping fault known as the Cascadia Subduction Zone, which extends from Northern California into Canada, the hole spewing boiling liquid is located 50 miles off the coast of Oregon.

The leak was first observed in 2015, but a new analysis led by the University of Washington (UW) suggests the chemically distinct liquid is 'fault lubricant.' 

This liquid allows plates to move smoothly, but without it, 'stress can build to create a damaging quake,' researchers said.

The team named the hole, which they describe as a hot spring, 'Pythias Oasis' after the ancient Greek oracle who 'prophesized' with the assistance of the mind-altering gases rising from a hot spring.

 

'It seems equally hallucinatory to find a spring of low-salinity, high-temperature, mineral-rich water flowing from the seafloor 3,280 feet below the surface off the coast of Oregon,' researchers shared in a statement.

A robotic diver uncovered the hole in a 2015 survey when sonar images captured bubbles rising from the seafloor.

Data showed liquid from the spring was coming from the plate boundary line and appeared warmer than the surrounding area.

 

Co-author Evan Solomon, a UW associate professor of oceanography who studies seafloor geology, said in a statement: 'They explored in that direction and what they saw was not just methane bubbles, but water coming out of the seafloor like a firehose. 'That's something that I have never seen and, to my knowledge, has not been observed before.'

 

Observations later determined the leaking fluid was 16 degrees Fahrenheit warmer than the surrounding seawater and was coming directly from the Cascadia megathrust, where temperatures are an estimated 300 to 500 degrees Fahrenheit. 

'Loss of fluid from the offshore megathrust interface through these strike-slip faults is important,' the statement notes, 'because it lowers the fluid pressure between the sediment particles and hence increases the friction between the oceanic and continental plates.' 

The Cascadia megathrust spans several major metropolitan areas, including Seattle and Portland, Oregon, but also touches parts of Northern California and Vancouver Island in Canada.