San Mateo–Hayward Bridge They provide power to the peninsula and San Francisco. The bridge was closed in the wake of the 1989 Loma Prieta earthquake as a precaution, but reopened on October 18, 1989. It underwent an extensive seismic retrofitting from 1997 through 2000 to protect against earthquake damage. The bridge was considered the worst evening commute in the Bay Area, which ended with the completion of a new eastern trestle carrying westbound bridge traffic in 2002. Eastbound bridge traffic took over the old trestle completely, although eastbound traffic was not expanded to three lanes until February 2003. Funded as part of BATA's
1989 Loma Prieta earthquake by the WGCEP in 1988 was coincidental. The contrasting characteristics of the 1906 and 1989 events were examined by seismologists Hiroo Kanamori and Kenji Satake. The significant amount of vertical displacement in 1989 was a key aspect to consider because a long-term sequence of 1989-type events (with an 80–100-year recurrence interval) normally result in regions with high topographic relief, which is not seen in the Santa Cruz Mountains. Three scenarios were presented that might explain this disparity. The first is that the geometry of the San Andreas Fault goes through a transition every several thousand years. Secondly, slip type could