Comments by "mpetersen6" (@mpetersen6) on "Forget Yellowstone - These EIGHT Supervolcanoes Could Destroy The World | Answers With Joe" video.

Of all know supervolcanoes there are more of them in Western North America than any where else*. I suspect this has a lot to do with the remnant of the Jaun de Fuca plate and perhaps other subducted Pacific Seafloor Plates that are still in the process of being absorbed back into the Mantle. But Yellowstone is a whole different ballgame. The hotspot that feeds Yellowstone has been active for a very long time. As North America has moved slowly to the Southwest due to its Plate motion the hot spot has repeatedly burned through the overlaying North American Plate leaving a trail of old caldera. Plus the hot spot likely fed the great Flood Basalts that buried parts of Washington. The only reason that the trail of old caldera fo not trace a fairly straight line to the Southwest is that the Pacific Northwest is rotating slowly in a clock wise motion. Approximently 50 million years ago the west coast of North America was in Eastern Eastern Washington. Various chunks of continental crust and island arcs have slowly been acreated to the western edge of the continent as the North Ametican Plate over ran the subducting Juan de Fuca Plate. One of the largest of these was a large volcanic province known as Siletzia. Portions of which comprise the Olympic Olympic Peninsula of Washington. For a good channel one PNW geology visit Nick Zentner's channel. He's a geology professor at UW Ellensburg *Yellowstone, Long Valley in California and Valles Calderas are just three. Some of the known North American supervolcanoes are likely extinct. Although there has been some activity in historic times. The various cinder cones in areas of the American West are evidence of this.
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