Qualla: Juan de Fuca Ridge

Juan de Fuca Ridge: Introduction

Wed, 18 Mar 2026 00:00:00 GMT

Photo credit Brocken Inaglory, CC BY-SA 4.0. In 1874, a Navy sloop called the USS Tuscarora was dragging a sounding line across the Pacific, surveying a route for an undersea telegraph cable to Japan, when the crew discovered a submarine mountain range about 200 miles off Cape Flattery. They noted it and moved on. Compared to the other features they'd charted during the voyage, this ridge seemed unremarkable. It would take another century before scientists understood what they had found: a place where the Earth's crust is being torn in two, where molten rock wells up from the mantle to build new ocean floor at a rate of six centimeters per year. The Juan de Fuca Ridge stretches roughly 500 kilometers off the coast of Washington, Oregon, and British Columbia, a seam in the planet's surface that is both creative and catastrophic -- building new crust with one hand while loading the Cascadia Subduction Zone with destructive potential with the other.

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Image: Brocken Inaglory | CC BY-SA 4.0

Juan de Fuca Ridge: A Plate with a Shrinking Future

Wed, 18 Mar 2026 00:00:00 GMT

Photo credit Brocken Inaglory, CC BY-SA 4.0. Thirty million years ago, the Juan de Fuca Ridge was part of a much larger system, the Pacific-Farallon Ridge, which drove the enormous Farallon Plate eastward beneath North America. Over geologic time, the Farallon Plate was consumed by subduction, breaking apart into smaller re...

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Image: Brocken Inaglory | CC BY-SA 4.0

Juan de Fuca Ridge: Chimneys in the Dark

Wed, 18 Mar 2026 00:00:00 GMT

Photo credit Ocean Networks Canada, CC BY-SA 2.0. The Endeavour segment, near the ridge's northern end, hosts some of the most intense hydrothermal activity on any mid-ocean ridge. More than 800 individual chimneys have been mapped in the central region alone, clustered across five major hydrothermal fields. Superheated water, l...

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Image: Ocean Networks Canada | CC BY-SA 2.0

Juan de Fuca Ridge: Catching a Volcano in the Act

Wed, 18 Mar 2026 00:00:00 GMT

Photo credit NOAA, Public domain. Scientists have been watching the Juan de Fuca Ridge erupt since 1986, when hydrothermal megaplumes on the Cleft segment revealed the first documented eruption. In June 1993, a 24-day eruption at the CoAxial segment drew research vessels that discovered microbial communities colo...

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Image: NOAA | Public domain

Juan de Fuca Ridge: Listening to the Seafloor

Wed, 18 Mar 2026 00:00:00 GMT

Photo credit Brocken Inaglory, CC BY-SA 4.0. You cannot see the Juan de Fuca Ridge. It lies beneath more than a kilometer of cold Pacific water, entirely invisible from the surface and from the air. But the U.S. Navy can hear it. The Sound Surveillance System -- SOSUS -- an array of Cold War-era hydrophones originally desig...

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Image: Brocken Inaglory | CC BY-SA 4.0