1989 Loma Prieta earthquake 3 was held in San Francisco on October 27 and Game 4 the following afternoon as the A's swept the Giants, four games to none. It is likely that the World Series game saved many lives, as Bay Area residents who would have normally been on the freeways were at home ready to watch the game when the earthquake hit. It is a rough estimate that thousands of people may have otherwise been on the Cypress Structure during the 5:00 p.m. rush-hour, as the structure was said to have carried 195,000 vehicles a day. Sources 1989 Loma Prieta earthquake The
1989 Loma Prieta earthquake was built on was filled marshland, and half was somewhat more stable alluvium. Because of new highway structure design guidelines—the requirement of ductile construction elements—instituted following the 1971 San Fernando earthquake, a limited degree of earthquake reinforcement was retrofitted to the Cypress Viaduct in 1977. The added elements were longitudinal restraints at transverse expansion joints in the box girder spans, but no studies were made of possible failure modes specific to the Cypress Viaduct. When the earthquake hit, the shaking was amplified on the former marshland, and soil liquefaction occurred. During the earthquake, the freeway buckled and twisted before the