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Effects of the 1959 Hebgen Lake, Montana earthquake

Hebgen Lake

This Mw 7.5 earthquake triggered an enormous landslide that buried a campground, causing 28 deaths and dammed the Madison River, forming Quake Lake. The earthquake, together with the nearby 1983 Ms 7.3 Borah Peak, Idaho, earthquake, illustrate the large earthquakes that occur in the intermountain seismic belt, part of the North America - Pacific plate boundary zone. The regional tectonics appear to reflect a complex interaction between the Yellowstone volcanic system and Basin and Range extension. About 6 m of normal fault motion on a NW-SE striking fault lowered the valley floor, dropping the houses shown into the lake. These dramatic effects are still visible today and make the site well worth visiting. A visitor center and parking lot are built on the slide.

Contributed by Seth Stein, Northwestern University