Today marks the 30th anniversary of the earthquake that is now considered a turning point in earthquake science and safety in the Bay Area. At 5:04 p.m. on October 17th, 1989, a magnitude 6.9 earthquake struck the San Francisco and Monterey Bay areas. It lasted 15 seconds and its epicenter was near the Loma Prieta peak in the Santa Cruz Mountains. At the time the earthquake hit, warm-ups were starting for the third game of the World Series being held at the now demolished Candlestick Park, a series that both Bay area teams were playing in, the Oakland Athletics and the San Francisco Giants. For the first time a major earthquake’s first jolt was televised.
The earthquake ultimately took 67 lives, injured more than 3,700, and caused greater than $5 billion dollars in damages. Forty-two of the deaths occurred when the double-deck I-880 freeway in Oakland collapsed. An upper section of the Bay Bridge also tumbled. Built on soil and minimal to no underlying bedrock caused the city’s most significant damage to be centralized in the Marina district. SF had enjoyed several decades of relative environmental peace and stability prior to this quake. The jarring results of the Loma Prieta quake drove significant changes in earthquake safety and research.
Following the Loma Prieta earthquake, a new era of research to gain insight into earthquakes, their aftershocks, and finding more accurate ways to predict them and find their epicenters began. Stanford, which was significantly impacted by the earthquake, led some of this research at the School of Earth Science. The U.S. Geological Survey has partnered with other organizations to assist in improving understanding of the threat of earthquakes, promoting awareness of safety measures, and developing strategies to reduce earthquake losses. Strict regulations were enacted in San Francisco and other communities to require buildings to be retrofitted and adhere to new standards. All bridges in the Bay Area were retrofitted to meet new standards for withstanding seismic activity.
More about the positive changes are well noted in an SFGate article that was recently published we shall defer to their research and reporting How 1989 Loma Prieta quake changed San Francisco — for the better.