Oakland, California Oakland to consistently be listed as one of America's most crime-ridden cities. In 1980 Oakland's black population reached its 20th-century peak at approximately 47% of the overall city population. The 6.9 Loma Prieta earthquake occurred on October 17, 1989. The rupture was related to the San Andreas fault system and affected the entire San Francisco Bay Area with a maximum Mercalli intensity of IX ("Violent"). Many structures in Oakland were badly damaged including the double-decker portion of Interstate 880 that collapsed. The eastern span of the San Francisco–Oakland Bay Bridge also sustained damage and was closed to traffic for one
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