There is a hole at the bottom of the Pacific and it is leaking liquid into the ocean. The hole lies 80km off the coast of Oregon, on the 965km Cascadia Subduction Zone fault line between Vancouver Island and northern California.
Researchers are worried that the hole could trigger a massive “megathrust” earthquake. This occurs when one tectonic plate moves under the other.
The researchers stumbled across the hole in the sea floor accidentally when they noticed a stream of what looked like methane bubbles. Methane seeps are very common in the region. A small submersible collected footage and samples. To the researchers’ surprise, it was not just methane. A liquid substance was gushing out of the seabed “like a firehose.”
Red dots denote methane seeps in the area. Image: https://www.usgs.gov/
The “water” coming from the hole has a different composition from seawater. It is also 9˚C warmer than the water around the hole and is more like freshwater than saltwater.
“That’s something that I’ve never seen and to my knowledge has not been observed before,” said oceanographer Evan Soloman.
A stressful situation
Liquid leaking into the world’s biggest ocean might not sound particularly dangerous, but this liquid — usually located about four kilometers below the seabed — acts as a lubricant and pressure regulator between tectonic plates. As the spring continues to leak, it puts more stress on the fault line.
“The megathrust fault zone is like an air hockey table,” Soloman 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. That’s when stress can build up.”
This is the first time anyone has found a seafloor leak like this. Seismologists are rapidly trying to find out more about the leak and its effects. They are also scouting for more undetected seeps like this along the fault line.
