Oregon and Washington states should be much more dangerous places to live. Located above a zone where the Pacific oceanic crust is sliding underneath the North American continent, the states should experience regular devastating earthquakes. That they don鈥檛, it seems, is down to the lubricating effect of the Yellowstone plume.
On the downside, this area of upwelling hot rock feeds the largest and potentially most dangerous volcanic system in North America.
Richard Allen of the University of California, Berkeley, and colleagues used seismic surveys to reconstruct the structure of the Juan de Fuca plate, a small chunk of Pacific oceanic crust sliding under North America. They found an unusually warm area just below the plate, probably produced by the Yellowstone plume 17 million years ago. Because the continents have moved, that plume now lies further east, under Wyoming, where it fuels the Yellowstone supervolcano.
Advertisement
The plume may have lubricated the Juan de Fuca plate, reducing its friction against the overlying North American plate and reducing the risk of earthquakes (Earth and Planetary Science Letters, ).
