Lessons not Learned from 1989 Loma Prieta Earthquake

Most of the damage sustained from the 1989 Loma Prieta Earthquake in Northern California was not a surprise to civil engineers and knowledgeable building officials. As early as the 1900s, engineers knew that unreinforced masonry buildings, and buildings built on poorly compacted soils are serious earthquake hazards. And the 1971 San Fernando Earthquake taught us that multiple‐deck highway structures similar to the infamous Cypress structure are incapable of sustaining lateral loads. Not only were the types of vulnerable structures known, but what was needed to be done to improve their seismic strength was known as well. The reasons for this inaction are numerous and semilegitimate, and the blame for it should be shared by the public who refused to pay the high cost of earthquake preparedness, by government officials who had their priorities in the wrong order, and by the engineering community who had historically opted not to play an active role in government and public policy. The fact that the epicenter of the earthquake was 60 mi (96.56 km) away from the densely populated San Francisco Bay area, and that the Cypress structure traffic on the day of the earthquake was much lighter than usual contributed to the controlled damage sustained. While the engineering and technical lessons learned from the earthquake are substantial and very valuable, the management and policy lessons went largely ignored.