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 1989 Loma Prieta earthquake The 1989 Loma Prieta earthquake occurred in Northern California on October 17 at local time (1989-10-18 00:04 UTC). The shock was centered in The Forest of Nisene Marks State Park approximately northeast of Santa Cruz on a section of the San Andreas Fault System and was named for the nearby Loma Prieta Peak in the Santa Cruz Mountains. With a moment magnitude of 6.9 and a maximum Mercalli intensity of IX ("Violent"), the shock was responsible for 63 deaths and 3,757 injuries. The Loma Prieta segment of the San Andreas Fault System had been relatively inactive