Accumulation of knowledge on earthquake activity in California has lead to stronger ground motions being postulated for the evaluation of the seismic stability of dams. A recent regional seismicity study for a 555 ft high earth and rockfill dam in central California lead to a ground motion with peak ground acceleration (PGA) of 0.50g originating in a local fault system 3 miles from the dam site. This PGA is more than 6 times higher than the PGA=0.08g value originally adopted when the Dam was analyzed for seismic stability 20 years ago. Thus, as part of FERC Part 12 evaluation requirements, the seismic stability of the Dam was re-evaluated using the updated ground motion and state-of-the-practice technology. This paper presents the analysis procedures and the results
