Performance of San Fernando Dams during 1994 Northridge Earthquake

The 1994 Northridge and 1971 San Fernando Earthquakes subjected the Lower and Upper San Fernando Dams of the Van Norman Complex in the San Fernando Valley, Calif., to strong near-source ground motions. In 1994 these earth darns, which were out of service and retained only a few meters of water, extensively cracked and settled due to the liquefaction of their hydraulic fill. The Lower San Fernando Dam moved over 15 cm upstream as the hydraulic fill liquefied beneath its upstream slope. The Upper San Fernando Dam moved even more acid deformed in a complicated three-dimensional pattern. The responses of the Lower and Upper San Fernando Dams during the 1994 Northridge Earthquake, although less significant than in 1971, provide the geotechnical engineering community with two useful case histories.