On the night of August 17, 1959, U.S. Geological Survey geologists Irving J. Witkind and Jack Epstein were camped on a small knoll above Hebgen Lake when their trailers began bouncing “like basketballs,” and they emerged to a shuddering landscape and a deafening roar from deep underground. After spending the summer studying the geologic features of this earthquake-prone land, they experienced the rare event of seeing their academic knowledge come vividly to life. Geologists still investigate the region’s seismic dynamics. The Hebgen and Red Canyon blocks dropped and tilted through a process called block faulting. At the eastern edge of the Basin and Range province, the earth’s crust is stretching and thinning, causing fault blocks to subside and tilt. Changes in several Yellowstone geysers after the 1959 earthquake suggested some relationship between the quake and Yellowstone geology, and after the earthquake Sapphire Pool erupted violently, with some bursts reaching over 125 feet high. Although the earthquake struck near Yellowstone, where a large chamber of molten rock known as the Yellowstone hot spot lies a short distance below the surface, and although a colossal eruption 640,000 years ago created a caldera covering most of the park whose parts have since risen and fallen, causing tremors and faulting in the rocks above, there is no evidence that the 1959 quake was directly caused by the dynamics of the hot spot.