Scientists fear a hole in a 600-mile fault line in the Pacific Ocean could trigger a catastrophic earthquake that would decimate cities in the northwestern US.
The hole spewing hot liquid is located 50 miles off the Oregon coastline and sits on the boundary of the submergence fault known as Cascadia Subduction Zone, which stretches from Northern California to Canada.
This geological feature could unleash a magnitude 9 earthquake in the Pacific Northwest — and the hole could be the fuel it needs.
The leak was first observed in 2015, but a new analysis led by the University of Washington (UW) suggests the chemically distinct fluid is “mislubricant.”
This fluid allows plates to move smoothly, but without it, “stress can cause a damaging earthquake,” researchers said.
The hole is located on the border of the Cascadia Subduction Zone and spews out a chemically distinctive fluid that could be “foul lubricant.” This fluid allows plates to move smoothly, but without it, “stress can cause a damaging earthquake,” researchers said
The team named the hole, which they describe as a hot spring, “Pythias oasis,” after the ancient Greek oracle who “prophesied” using the mind-altering gases rising from the hot spring below.
“It seems equally hallucinatory to find a source of low-salinity, high-temperature mineral-rich water flowing from the seafloor 3,280 feet below the surface off the Oregon coast,” researchers shared in a rack.
A robotic diver discovered the hole in a 2015 study when sonar images captured bubbles of air rising from the seafloor.
Data showed that fluid from the source emerged from the boundary line of the plate 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 were not just methane bubbles, but water coming out of the seafloor like a fire hose.
“That’s something I’ve never seen and, as far as I know, not seen before.”
Observations later determined that the leaking fluid was 16 degrees Fahrenheit warmer than the surrounding seawater and came directly from the Cascadia megathrust, where temperatures are estimated to be 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 thus 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 Canada’s Vancouver Island.
Solomon compared the megathrust fracture zone to an air hockey table
Scientists said this is the first known location of its kind and fear a megaquake could occur
A robotic diver discovered the hole in a 2015 study when sonar images captured bubbles of air rising from the seafloor. Data showed that fluid from the source emerged from the boundary line of the plate and appeared warmer than the surrounding area
A significant fluid leak off central Oregon could explain why the northern part of the Cascadia Subduction Zone, off the coast of Washington, is believed to be more strongly occluded or linked than the southern part off the Oregon coast, experts said.
“When the fluid pressure is high, it’s like turning on the air, which means there’s less friction and the two plates can slip,” he said.
“When the fluid pressure is lower, the two plates lock – then tension can arise.”
The Cascadia subduction zone is an area where two tectonic plates collide.
The Juan de Fuca, a small oceanic plate, is being pushed under the North American plate on top of the continental US.
Subduction systems – in which one tectonic plate slides over another – can produce the world’s largest known earthquakes. A good example is the 2011 Tohoku earthquake that shook Japan to its foundations and killed an estimated 20,000 people.
Cascadia is seismically quiet compared to other subduction zones, but it is not completely inactive.
Research indicates that the rupture broke in 1700 at a magnitude of nine, about 30 times more powerful than the largest predicted earthquake in San Andreas.
Solomon said fluid released from the fracture zone is the first known location of its kind.
Observations determined that the leaking fluid was 16 degrees Fahrenheit warmer than the surrounding seawater and came directly from the Cascadia megathrust
The hole, spewing hot fluid, is 50 miles off the Oregon coast
However, he theorizes that similar sources may be lurking nearby, but are more difficult to detect from the ocean’s surface.
A significant fluid leak off central Oregon could explain why the northern portion of the Cascadia Subduction Zone, off the coast of Washington, is believed to be more strongly occluded or linked than the southern portion off the Oregon coast.
Co-author Deborah Kelley, a UW professor of oceanography, said: ‘Pythias Oasis provides a rare window into processes operating deep in the seafloor, and the chemistry suggests this fluid is coming from close to the plate boundary.
“This suggests that the proximate faults regulate fluid pressure and megathrust slip behavior along the central Cascadia subduction zone.”