These strike-slip faults, where sections of ocean crust and sediment slide past each other, exist because the ocean plate hits the continental plate at an angle, placing stress on the overlying continental plate. Instead, they occur near vertical faults that crosshatch the massive Cascadia Subduction Zone. The new seeps aren’t related to geologic activity at the nearby seafloor observatory that the cruise was heading toward, Solomon said. Calculations suggest the fluid is coming straight from the Cascadia megathrust, where temperatures are an estimated 150 to 250 degrees Celsius (300 to 500 degrees Fahrenheit). Observations from later cruises show the fluid leaving the seafloor is 9 degrees Celsius (16 degrees Fahrenheit) warmer than the surrounding seawater. The feature was discovered by first author Brendan Philip, who made the discovery as a UW undergraduate student and now works as a White House policy advisor. That’s something that I’ve never seen, and to my knowledge has not been observed before,” said co-author Evan Solomon, a UW associate professor of oceanography who studies seafloor geology. “They explored in that direction and what they saw was not just methane bubbles, but water coming out of the seafloor like a firehose. Further exploration using an underwater robot revealed the bubbles were just a minor component of warm, chemically distinct fluid gushing from the seafloor sediment. The ship’s sonar showed unexpected plumes of bubbles about three-quarters of a mile beneath the ocean’s surface. The team made the discovery during a weather-related delay for a cruise aboard the RV Thomas G. Observations suggest the spring is sourced from water 2.5 miles beneath the seafloor at the plate boundary, regulating stress on the offshore fault. 25 in Science Advances, describes the unique underwater spring the researchers named Pythia’s Oasis. The Cascadia Subduction Zone - the eerily quiet offshore fault that threatens to unleash a magnitude-9 earthquake in the Pacific Northwest - still holds many mysteries.Ī study led by the University of Washington discovered seeps of warm, chemically distinct liquid shooting up from the seafloor about 50 miles off Newport, Oregon. The field of plate tectonics is not that old, and scientists continue to learn the details of earthquake-producing geologic faults. This discovery does not change the current risk of a large earthquake on the Cascadia Subduction Zone].Scientists are not alarmed at discovering this geologic feature, which does not trigger earthquakes but may regulate friction in the fault zone.Researchers believe this fluid comes directly from the Cascadia megathrust zone, or plate boundary, and helps control stress buildup between the two plates. These bubbles are a byproduct of a unique site where warm, chemically distinct fluid gushes from the seafloor. This sonar image of the Pythias Oasis site shows bubbles rising from the seafloor about two-thirds of a mile deep and 50 miles off Newport, Oregon.
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