Map of Juan de Fuca Plate (IMAGE) University of California - Berkeley Caption The Juan de Fuca and Gorda plates offshore of the Pacific Northwest. The plate moves eastward from the midocean ridge and spreading center on the plate's western edge to the trench on the eastern margin where the plate subducts under the North American plate. The Cascadia subduction zone is capable of generating magnitude 9 quakes, which can also produce deadly tsunamis. Credit UC Berkeley Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.