Earth Is Breaking Apart Under the Pacific Northwest Across a Fault That Is Ripping Deeper Than Anyone Expected

Key Points:

• Scientists captured the first clear images of the Juan de Fuca tectonic plate splitting apart deep beneath the seafloor off Vancouver Island, revealing a subduction zone in the process of breaking up piece by piece.
• The study, published in Science Advances, shows that the plate is tearing in stages rather than shutting down all at once, with large faults causing sections to detach over millions of years, a process termed episodic or piecewise termination.
• Using seismic imaging from the 2021 Cascadia Seismic Imaging Experiment, researchers identified faults and fractures, including a major fault where the plate has dropped about five kilometers and is nearing complete breakage.
• Quiet zones in the earthquake record correspond to areas where the plate has already detached, indicating that the rupture is spreading and causing the gradual shutdown of the subduction system.
• While the findings do not change the immediate earthquake risk in the Pacific Northwest, they provide new structural insights that could improve seismic hazard models and earthquake behavior forecasts in the region.