The Cascadia Megathrust and Tectonic Stress in the Pacific Northwest
Tectonic Setting and Stress Field
 Explanation
Inward pointing red arrows: Orientation of principal compressive stress
Outward pointing red arrows: Orientation of principal tensional stress
Inward pointing green arrows: Orientation of principal compressive in Puget Sound
Yellow arrows: Relative plate motion between the oceanic plates (Pacific and Juan de Fuca) and the North American plate
Stress Provinces
Pacific Northwest Stress Province: N-S oriented compressive stress
Cascade Convergence Stress Province (CCP): NNE-SSW oriented compressive stress
Basin and Range Stress Province: E-W oriented tensional stress
Canadian Mid-Plate Stress Province: NE-SW oriented compressive stress
Questions
- Is the N-S oriented compressive stress in the Pacific Northwest Stress Province related more to Pacific-North America relative plate motion than Juan de Fuca-North America relative plate motion?
- Is the direction of stress in the Cascade Convergence Stress Province related to increase coupling along the subduction zone offshore of Washington?
(See Answers to these questions on another page.)
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U.S. Department of the Interior | U.S. Geological Survey