9416509 Synolakis The objective of this project is to model the response of the Los Angeles dam during the 1994 Northridge Earthquake. This dam is located about 6 miles from the epicenter of the earthquake, and is inside the Van Norman complex of the Department of Water and Power (DWP). Lateral spreading, liquefaction and permanent ground settlement were observed in the entire area of the Van Norman complex. The focus of this study is the impulsive motion of the water surface in response to the earthquake-induced ground motion, and the investigation of any seiche which may have been produced. The sloshing of the water surface following the earthquake produced 10 foot vertical runup distances measured around the south-east side of the reservoir by the principal investigator. This observation implies that the measured runup was about 12% of the depth: this is the primary motivation for this study. This project has three specific objectives: 1. To use the estimated ground motions under the dam to determine if overtopping occurred during the earthquake. 2. To determine the profile of the tsunami wave or seiche which can be produced in reservoirs with ground motions having significant vertical accelerations. 3. If time permits, to use the measured runup heights and the hydrodynamic model to infer the low-frequency content of the earthquake spectra at this site (data which is not readily available from measured strong-motion records), and to provide another method for estimating the rotation and shift component of the ground motion. ***
