Forty-five earthquakes of moderate intensity (V or greater) on the Modified Mercalli Intensity Scale (MM) and extent have originated in Wyoming from 1894 to 1976. Many shocks have occurred in Yellowstone National Park, including an intensity VII event in June 1975. the 1959 Hebgen Lake, Mont., earthquake, centered just west of the park, was felt (MM VII) in northwestern Wyoming. Many aftershocks from this earthquake were reported in Yellowstone Park (MM V-VI) through December 1959, and numerous shocks of lesser intensities continued through 1963.