Cathryn,
I did not give enough information. My question was for the quake map of the USA. When you pull it up you see all of the quakes in California. Then there is the arc going through Utah. Then there are the Yellowstone quakes and on into Montane tending west to Washington and the Seattle area and then down through Oregon. Seems to be a BIG doughnut. My question was is it just chance or can the douthnut theory work for a big one also?
Bob in Woodland Hills