Topline
A leak in the Pacific Ocean’s floor has scientists concerned it could fuel “the big one,” a magnitude-9.0 earthquake that would be one of the strongest earthquakes the U.S. has ever seen, and has been the source of fears in the Pacific Northwest for years.
The leak in the Cascadia Subduction Zone fault.
Key Facts
A leak at the bottom of the Pacific Ocean around 50 miles off the coast of Oregon is spewing what was originally thought to be water, but a recent paper published in Science Advances suggests it is warm tectonic lubricant.
It was previously believed the “chemically distinct fluid” was 16 degrees fahrenheit warmer than the surrounding ocean water, but the paper found the liquid is coming from the Cascadia megathrust (the boundary between two of Earth’s tectonic plates), where temperatures are estimated to be around 300 and 500 degrees fahrenheit.
The leak was first identified in 2015 by the University of Washington and is called Pythia’s Oasis after the Greek oracle—it was found on top of the 600-mile-long Cascadia Subduction Zone fault.
The researchers discovered the leak during a weather-related delay for a cruise when the ship’s sonar found unexpected bubbles beneath the ocean’s surface, but it turns out the bubbles were just the tip of the iceberg as water was shooting out from the seafloor like a “firehose,” co-author of the Science Advances paper Evan Soloman said in a statement in a press release.
According to the press release, the researchers believe this is the first known leak of its kind in this ocean, though they believe it’s possible there are more nearby.
Earthquake Concerns
The megathrust is the area between the Juan de Fuca tectonic plate and the North American plate. The fault’s loss of fluid could lower the fluid pressure between the two plates, which can then cause friction, the researchers said in the paper. “If the fluid pressure is lower, the two plates will lock—that’s when stress can build up,” Soloman said in the press release. The fluid allows the plates to glide against each other smoothly, so without it, the plates could lock, creating stress that can result in a magnitude-9.0 earthquake. Michigan Tech University's Earthquake Magnitude Scale categorizes earthquakes with a magnitude of 8.0 and up as “great” earthquakes that can “totally destroy” communities close to the epicenter—these types of earthquakes only happen once or twice a year.
Tangent
A massive earthquake in this region has been of concern for many years, and was popularized in a 2015 New Yorker story, which warned that if it hit the “Pacific Northwest, the area of impact will cover some hundred and forty thousand square miles, including Seattle, Tacoma, Portland, Eugene, Salem (the capital city of Oregon), Olympia (the capital of Washington), and some seven million people,” and could cause the “worst natural disaster in the history of North America, outside of the 2010 Haiti earthquake, which killed upward of a hundred thousand people.” It could create a devastating tsunami, like what happened in Japan in 2011. The magnitude-9.0 earthquake—named the Tohoku earthquake—was Japan’s strongest earthquake in history and the third largest since 1900. It was triggered by underwater tectonic activity in the North Pacific, similar to what’s occurring at the Cascadia Subduction Zone fault. This resulted in a tsunami with waves reaching 132 feet high. According to the National Centers for Environmental Information, the earthquake and tsunami caused the deaths of over 18,000 people, including thousands of people who were never found. They destroyed 123,000 homes and damaged millions more, causing $220 billion in damage. It also caused $31 million in damage in Hawaii and $100 million in damages and recovery in California, making it the most expensive natural disaster in history, according to insurance company Marsh McLennon’s BRINK News.
Cascadia Subduction Zone Fault Earthquake Of 1700
Researchers are wary about the discovery of the leak because the Cascadia Subduction Zone fault was the site of one of the most devastating earthquakes in history. In 1700, a magnitude-9.0 earthquake struck Vancouver Island and caused a tsunami, which completely destroyed the winter village of the Pachena Bay people, leaving no survivors. The earthquake and tsunami also struck the West Coast of the U.S., making it the second strongest earthquake in U.S. history. Some of the notable damage in the U.S. is “ghost” forests in Oregon and Washington. The lush trees in these forests were thought to have been instantly killed when struck by saltwater, leaving a forest of tree stumps, which are still visible today, according to the College of Earth and Mineral Science at Pennsylvania State University.
Key Background
The largest earthquake to strike the U.S. occurred in 1964 in the Prince William Sound region of Alaska, according to the United States Geographical Survey. The magnitude-9.2 earthquake lasted 4.5 minutes and is the second most powerful earthquake ever recorded after the magnitude-9.5 earthquake in Chile in 1960. The earthquake and following tsunami resulted in $311 million in damage (equivalent to $3 billion in 2023 dollars), and caused 131 deaths. They caused damage at Alberni and Port Alberni, Canada, Hawaii and along the West Coast of the U.S., where 15 people were killed. The highest recorded waves reached 219 feet high. It even caused the Space Needle in Seattle, Washington to sway and caused bodies of water as far east as the Texas coast to slosh over. All states except Rhode Island, Delaware and Connecticut registered the earthquake.
Further Reading
The Really Big One (The New Yorker)
