October 17, 1989 Loma Prieta Earthquake

On October 17, 1989, at 5:04:15 p.m. (PDT), a magnitude 6.9 earthquake severely shook the San Francisco and Monterey Bay regions. The epicenter was located near Loma Prieta peak in the Santa Cruz Mountains, approximately 14 km (9 mi) northeast of Santa Cruz and 96 km (60 mi) south-southeast of San Francisco.

The 1989 Loma Prieta earthquake ended decades of tranquility in the San Francisco Bay region. It was a wakeup call to prepare for the potentially even more devastating shocks that are inevitable in the future. Since 1989, the work of the U.S. Geological Survey and other organizations has improved understanding of the seismic threat in the Bay region, promoted awareness of earthquake hazards, and contributed to more effective strategies to reduce earthquake losses. These efforts will help reduce the impact of future large quakes in the San Francisco Bay region. Robert Page, U.S. Geological Survey

• ShakeMap

  Map showing ground motion and shaking intensity based on instrumental measurements of shaking along with information about local geology and the earthquake's location and magnitude.

• Ground motion simulations

  Movie showing shaking intensity as the seismic waves traveled away from the fault over time.

• Did you feel it?

  Map of shaking intensity based on reports from people who experienced the earthquake.

• USGS Photos of Loma Prieta Earthquake Damage

  More than 100 photos available online (and on CD) portray some of the damage resulting from the earthquake.

• USGS Professional Papers on Loma Prieta

  Four Loma Prieta Earthquake Professional Papers, each containing multiple chapters, document the magnitude 6.9 earthquake that shook the San Francisco and Monterey Bay regions.

  1. Professional Paper 1550: Earthquake Occurrence
  2. Professional Paper 1551: Strong Ground Motion and Ground Failure
  3. Professional Paper 1552: Performance of the Built Environment
  4. Professional Paper 1553: Societal Response

See Also

• Progress Towards a Safer Future Since the 1989 Loma Prieta Earthquake

  Earthquakes remain a serious threat to the San Francisco Bay region. This USGS Factsheet examines earthquake hazards in the region, including probabilities, preparedness, and building codes.

• Faultline: Remembering Loma Prieta

  A personal account, by Mary K. Miller, of the events unfolding.

• 1989 Earthquake Reports and Photographs

  From the Virtual Museum of the City of San Francisco.

• Berkeley Seismological Laboratory

  More information about the earthquake, including location parameters, maps, photos, and seismograms.

• Santa Cruz Mountains (Loma Prieta), California

  Summary and historical account of the earthquake including photos.