1989 Loma Prieta earthquake the State office of Emergency Services issued (for the first time in Bay Area history) short term advisories for a possible large earthquake, which meant there was "a slightly increased likelihood of an M6.5 event on the Santa Cruz Mountains segment of the San Andreas fault". The advisories following the two Lake Elsman events were issued in part because of the statements made by WGCEP and because they were two of the three largest shocks to occur along the 1906 earthquake's rupture zone since 1914. The 5.3 June 1988 and the 5.4 August 1989 events also occurred on previously unknown
1989 Loma Prieta earthquake removed and replaced the collapsed section, and re-opened the bridge on November 18. The worst disaster of the earthquake was the collapse of the two-level Cypress Street Viaduct of Interstate 880 in West Oakland. The failure of a section of the viaduct, also known as the "Cypress Structure" and the "Cypress Freeway", killed 42 and injured many more. Built in the late 1950s, the Cypress Street Viaduct, a stretch of Interstate 880, was a double-deck freeway section made of nonductile reinforced concrete that was constructed above and astride Cypress Street in Oakland. Roughly half of the land the Cypress Viaduct