 North of the Mendocino Triple Junction , the Gorda plate is subducting beneath the North American Plate at the Cascadia subduction zone , with a convergence rate of 2 @.@ 5 – 3 centimeters ( 0 @.@ 98 – 1 @.@ 18 in ) per year , but comparisons with other subduction zones have led to a belief that the convergence may be taking place aseismically . The distinct lack of interplate events there has generated contention regarding the zone 's seismic hazard , though there are strong indications that substantial historic events have occurred in the Pacific Northwest . Submerged wetlands and raised marine terraces both illustrate the presence of past events , and radiocarbon dating of rock layers has revealed that three seismic events took place in the last 2 @,@ 000 years , with the most recent event being the 1700 Cascadia earthquake . The Gorda Plate is undergoing a process of intraplate deformation and experiences large intraplate earthquakes that may be the result of north @-@ south compression of the oceanic crust along the Mendocino Fracture Zone . 
