1989 Loma Prieta earthquake larger loss of life, as several of the Bay Area's major transportation structures suffered catastrophic failures. The collapse of a section of the double-deck Nimitz Freeway in Oakland was the site of the largest number of casualties for the event, but the collapse of man-made structures and other related accidents contributed to casualties occurring in San Francisco, Los Altos, and Santa Cruz. The history of earthquake investigations in California has been largely focused on the San Andreas Fault System, due to its strong influence in the state as the boundary between the Pacific Plate and the North American Plate; it
1989 Loma Prieta earthquake Old Town district of Salinas, and some were later demolished. The San Francisco–Oakland Bay Bridge suffered severe damage, as a section of the upper deck on the eastern cantilever side fell onto the deck below. The quake caused the Oakland side of the bridge to shift to the east, and caused the bolts of one section to shear off, sending the section of roadbed crashing down like a trapdoor. Traffic on both decks came to a halt, blocked by the section of roadbed. Police began unsnarling the traffic jam, telling drivers to turn their cars around and drive back the