Loma Prieta: The Earthquake That Shook the Bay Area

The Shock

At 5:04 p.m. local time on October 17, 1989, a magnitude 6.9 earthquake struck the San Francisco and Monterey Bay regions. Its epicenter lay in the Santa Cruz Mountains.

Damage Beyond the Epicenter

The earthquake damaged transportation, buildings and utilities across a wide area. Distance from the rupture alone did not determine the severity of damage at every location.

The Human Cost

The U.S. Geological Survey records 63 deaths. Accounts should preserve the distinction between observed losses and later simulations of what shaking may have looked like.

Photographs and Models

USGS collections include documentary photographs, while modern ground-motion visualizations reconstruct physical processes computationally. Both are useful, but a simulation is not original footage.

The Work Afterward

Research after Loma Prieta improved understanding of regional earthquake hazards. The anniversary concerns both a disaster and the sustained work of reducing losses from future shaking.