Dams could have subtle or hidden earthquake damage

The California Governor’s Office of Emergency Services (CalOES) and the Federal Emergency Management Agency (FEMA) sent out a news release urging people in Napa and Solano Counties to look closer for earthquake damage following the South Napa Earthquake last August.

“When earthquakes occur, some of the damage happens in areas of our homes and businesses that may be nearly impossible to spot without close attention. Residents and business owners in Napa and Solano Counties continue to discover damage from the South Napa Earthquake,” the news release said.

The 1994 Northridge earthquake cracked the surface pavement on the upstream slope of the Los Angeles Dam. (Photo Courtesy of Los Angeles Department of Water and Power.)
The 1994 Northridge earthquake cracked the surface pavement on the upstream slope of the Los Angeles Dam. (Photo Courtesy of Los Angeles Department of Water and Power.)

The same may be true of dams, no matter what their hazard classification. After any seismic activity of note, whether in California or any other state, dam inspections will be very important. State dam safety officials or private engineers should be asked to check for damage that might lead to an emergency situation or failure.

Dam owners should be doing their own inspections before and after the engineers take a look. Subtle damage that deteriorates further may create dangerous conditions later. Aftershocks also may create conditions that require additional inspections. Liability and responsibility for the safety of dams always remains with the dam owner, whether an individual, a neighborhood association, or a municipal or county government.