The seep, called Pythia’s Oasis, lies roughly 3,000 feet below the ocean surface. Its fluid is believed to originate about two miles beneath the seafloor, where tectonic plates meet along the Cascadia Subduction Zone. Scientists discovered the feature in 2014, and it became more widely known after research published in 2017 and further study in 2023.

The subject resurfaced on social media earlier this month when two Pacific Northwest influencers posted a video about the seep. The clip drew hundreds of thousands of views, reviving curiosity about the phenomenon without suggesting an imminent disaster.

Scientists say the seep has likely been flowing for at least 1,500 years. It does not increase the likelihood of a major Cascadia earthquake, often called “The Big One,” along the roughly 700-mile subduction zone stretching from Northern California to British Columbia.

Instead, Pythia’s Oasis offers researchers an unusual opportunity to study fluids and conditions deep beneath the seafloor. Deborah Kelley, a University of Washington oceanography professor, described it in 2023 as “one of the first times where we have a direct window down into the conditions and the fluids that are generated in this environment.”

The vent is about two inches wide, but the liquid flowing from it is distinctive. Unlike the cold fluids more commonly found at seafloor seeps, Pythia’s Oasis releases water about four times warmer than the surrounding seawater. Its chemistry includes elements such as boron and lithium that are uncommon in other seafloor seeps.

“The chemistry of these fluids is unlike anything I’ve ever seen in the ocean, anywhere,” Kelley said.

The name refers to Pythia, the priestess at the ancient Greek Temple of Apollo at Delphi, which was built above the meeting point of two faults. For scientists studying Cascadia, the seep’s importance is not as a warning sign, but as a rare natural opening into a difficult-to-reach geological environment.