A seafloor hole shooting up warm, mineral-rich liquid into the Pacific Ocean near Oregon’s central coastal might not be a good sign for earthquake activity in the region, scientists say.
The hole, named “Pythia’s Oasis” after the ancient Greek high priestess who speaks the prophecies while inhaling the vapor rising from a hot spring, is described as a “warm, high-discharge, water-dominated seafloor seep” located about 50 miles off Newport, Oregon. It also sits on top of the 600-mile Cascadia Subduction Zone fault, a source of major earthquake events up to magnitude 9.0 or greater.
In their latest study to explain the vent’s nature, researchers at the University of Washington (UW) suggest that the liquid leaking out of it may be acting as a lubricant between the oceanic and continental plates, and that less lubricant means more pressure accumulated to produce a devastating earthquake.
“The megathrust fault zone is like an air hockey table,” the professor explained. “If the fluid pressure is high, it’s like the air is turned on, meaning there’s less friction and the two plates can slip.”
“If the fluid pressure is lower, the two plates will lock,” he added. “That’s when stress can build up.”
“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’ve never seen, and to my knowledge has not been observed before,” Solomon said.
Later expeditions to the spring revealed that the fluid shooting out of it is 9 degrees Celsius (16 degrees Fahrenheit) warmer than surrounding seawater. According to the team’s calculations, the fluid appears to come straight from the Cascadia megathrust fault, where temperatures are an estimated 150 to 250 degrees Celsius (300 to 500 degrees Fahrenheit).
The last earthquake that occurred in this fault was in 1700, with an estimated 9.0 magnitude. The impact of this event was felt by those living on both sides of the Pacific, with Japanese historical records indicating that a destructive distantly-produced tsunami struck their coast on Jan. 26 of that year.
The Cascadia Subduction Zone has not produced an earthquake since 1700, although it is building up pressure where the Juan de Fuca Plate is locked against the North American plate.
According to the government of Oregon, researchers are predicting that there is about a 37 percent chance that a megathrust earthquake of 7.1+ magnitude in this fault zone will occur in the next 50 years.