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Grand Teton National Park Report

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The 55 km-long Teton normal fault at the eastern base of the Teton Range, Wyoming, has one the highest rates of Holocene slip of any fault in the Basin-Range, but it is seismically dormant at the M2 + level and presently lies in the center of a 50 km-long seismic gap (Byrd et al, 1993). Analyses of trenching, fault scarp heights, and fault proftles indicate earthquakes on the Teton fault are non­Poissonian, with from 5 to 10 M >7 earthquakes occurring from 7,900 to 14,000 years ago, but only two such events between 5,000 and 7,900 years ago, and none in the last 5,000 years (Byrd et al., 1994).