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The Cascadia subduction zone is a 960 km (600 mi) fault at a convergent plate boundary, about 100–200 km (70–100 mi) off the Pacific coast, that stretches from northern Vancouver Island in Canada to Northern California in the United States
Magnetic anomalies around the Juan de Fuca and Gorda Ridges, off the west coast of North America, color coded by age. There are some unusual features at the Cascade subduction zone. Where the Juan de Fuca Plate sinks beneath the North American Plate there is no deep trench, seismicity (earthquakes) is less than expected, and there is evidence ...
For decades, scientists have warned about the potential of the Cascadia Subduction Zone, a megathrust fault that runs offshore along the coast from northern Vancouver Island to Cape Mendocino ...
Within the portion of North American crust overlying the Gorda slab, motion on faults is reverse, and in April 1992, a M 7.1 earthquake ruptured the southern portion of the Cascadia subduction zone. Similar to the general seismicity patterns in the region, the majority of the aftershocks for this event had vertical strike-slip motions and were ...
A 2004 study revealed the potential for relative mean sea level rise (caused by subsidence of coastal land) along the Cascadia subduction zone. It postulated that cities on the west coast of Vancouver Island, such as Tofino and Ucluelet, are at risk for a 1-to-2-metre (3 ft 3 in to 6 ft 7 in) subsidence, relative to mean sea level. [22]
Since the North American west coast has a convoluted structure, significant work has been required to resolve the complexity. [2] Tomographic imaging of the subducted Farallon plate beneath North America, showing that the velocities of sesimic waves vary based on the temperature of the material they are moving through.
A map of the Juan de Fuca plate with noted seismic incidents, including the 2001 Nisqually earthquake. The Juan de Fuca plate is bounded on the south by the Blanco fracture zone (running northwest off the coast of Oregon), on the north by the Nootka Fault (running southwest off Nootka Island, near Vancouver Island, British Columbia) and along the west by the Pacific plate (which covers most of ...
The Franciscan Complex is an assemblage of metamorphosed and deformed rocks, associated with east-dipping subduction zone at the western coast of North America. [6] Although most of the Franciscan is Early/Late Jurassic through Cretaceous in age (150-66 Ma), [ 7 ] some Franciscan rocks are as old as early Jurassic (180-190 Ma) age and as young ...