When the plate of the coast of northern California, Oregon and Washington is done diving under the continental crust. The cascade volcanoes will all shut off. Go extinct from the lack of fuel basically. The queen Charlotte Fault from up by Alaska and the San Andreas Fault down south in California will all become one big Fault line with parts of California sliding up the line towards the Northwest. Has happened before a couple times in the ancient past. Can find rocks on the Washington coast and San Juan Islands that were originally way down by Baja California and Mexico