Empirical Earthquake Ground Motions for an Engineering Site with Fault Sources: Tooele Army Depot, Utah

Empirical earthquake ground motions were developed for an engineering site at Tooele Army Depot near Tooele, Utah. Nearby fault sources were judged capable of generating earthquakes, as was the Wasatch fault. Comparisons were made between peak horizontal motions obtained from charts giving motions for Modified Mercalli intensity and charts giving motions for earthquake magnitude and distance. The latter motions were compared for charts by various authors. The motions that were generated include the effects of a major earthquake on the Wasatch fault at 50 km from the site, with M = 7.5, and a local earthquake at 21 km from the site, also of M = 7.5. The Wasatch earthquake for a soft site involves peak horizontal motions with acceleration = 380 cm/sec 2 , velocity =58 cm/sec and duration (≥0.05 g ) = 56 sec. The local earthquake has an acceleration = 1,100 cm/sec 2 , velocity = 180 cm/sec and duration (≥0.05 g ) = 54 sec. Appropriate time histories are recommended. Operating basis motions are also provided.