The Borah Peak, Idaho Earthquake of October 28, 1983—Buildings and Schools

Abstract

At 8:07 AM MDT, October 28, 1983, a major earthquake (Ms = 7.3) rocked central Idaho. The earthquake source zone was near the base of Mt. Borah with an elevation of 12,662 ft (3859 m). This earthquake is the largest earthquake to occur in Idaho in recorded history, and is the strongest to occur in the continental United States since the magnitude 7.1 Hebgen Lake Montana earthquake of 1959. It was felt that a study of the effects of such a large magnitude earthquake on buildings and communities would enhance understanding of the response of buildings to different types of earthquakes. Therefore, an EERI reconnaissance team was dispatched to the earthquake area on the day following the event. Performance of buildings and other structures near the earthquake source zone is discussed.