Pythias Oasis

This week, there has been a lot in the news about warm liquid spewing up from the ocean floor off the coast of central Oregon. Even late-night hosts have picked it up.

Hahaha, Stephen Colbert! A quick note: Subduction zones occur when one plate dives under (subducts) another. These faults are called reverse or thrust faults. Since the Cascadia Subduction Zone creates massive earthquakes, its fault is termed a megathrust fault.

While some reporting around this research has been factual, other news (I won’t post links to them here) has dramatized the research. I’m posting this in hopes of dispelling some of that dramatization.

How The Spring Got Its Name

According to the University of Washington’s Interactive Oceans website,

In ancient Greece, the Pythia was the oracle at Delphi who sat in a temple built above a seismic fissure and ‘prophesized’ with the assistance of the mind-altering gases rising from the hot spring below. It seems equally hallucinatory to find a spring of low-salinity, high-temperature, mineral-rich water flowing from the seafloor 1000 meters below the surface off the coast of Oregon, which is why the name “Pythias Oasis” is so apt. 

The Research

The research paper behind all the news was published in Science Advances on January 25, 2023. Scientists from the University of Washington headed the research, and UW posted a press release this week that’s worth a read. Some basic facts from the release:

  • The spring occurs near vertical, strike-slip faults that “crosshatch the massive Cascadia Subduction Zone”.
  • The spring was discovered in 2015… so it’s been spewing for at least that long. The research paper discussed above suggests it’s been spewing for much longer, saying, “The BSR anomalies that indicate sustained flow for ~1500 years at Pythia’s Oasis support this interpretation.” Just because the news is new to us doesn’t mean the geologic process is.
  • The loss of fluid “lowers the fluid pressure between the sediment particles and hence increases the friction between the oceanic and continental plates”. This is not the only reason we know that stress is building (and has been for centuries) on the fault. GPS allows scientists to see the plate movement and compression occurring.
  • Its chemistry suggests this fluid comes from near the plate boundary.
  • It is the first known spring of its kind. That said, they are difficult to find, and scientists didn’t know of their existence before finding Pythias Oasis… so they weren’t searching for them. There may be more out there around the world.

A quote from the research paper:

While we do not know whether Pythia’s Oasis is the only seep of its kind, it is possible that similar seeps exist along the three strike-slip faults in the central CSZ. Therefore, strike-slip faults may play a consequential role in the regulation of overpressures throughout the forearc in the central CSZ and should be considered in future models of the CSZ.

Research of this kind takes time to conduct. Some of the more alarming articles make it sound like the research team discovered the spring, conducted research, and posted their findings all this month. The reality is that this research has taken place over a period of 8 years and is ongoing. Research requires assembling research teams, collaboration with other scientists, and funding. Lots of funding. It’s complex.

When you find a news article that says something like “red alert”, I highly recommend checking the information against reputable organizations. “Red Alert” is not, to my knowledge, a term used by professionals in the field, and to date, earthquakes are not predictable.

Scientists have known for decades that there is a growing risk of an earthquake. Stress continues to build every year. Some day that stress will become too much, and the fault will rupture. Details on that risk (failure analyses & log-normal formulas) can be found on Surviving Cascadia’s Likelihood of an 8.0, Likelihood of a 9.0, and Timing The Next Big One pages.

As I’ve said before, it’s good to become familiar with this risk. We choose to prepare—or not—based on that perceived risk, so understanding can be key to Surviving Cascadia.

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