The Pacoima Dam withstood , but was damaged by , the very strong ( > 1 '' g '' ) ground movement which occurred during both the 1971 San Fernando and 1994 Northridge earthquakes . Because of concerns about the stability of the dam and especially its response to potential future earthquakes , the County of Los Angeles , with the technical support of the USGS , began monitoring the dam using continuous GPS
1994 Northridge earthquakes
1994 Northridge earthquake
Pacoima Dam