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
Earthquake prediction of having observed such phenomena prior to an earthquake, no such phenomena has been shown to be an actual precursor. A 2011 review found the "most convincing" electromagnetic precursors to be ULF magnetic anomalies, such as the Corralitos event (discussed below) recorded before the 1989 Loma Prieta earthquake. However, it is now believed that observation was a system malfunction. Study of the closely monitored 2004 Parkfield earthquake found no evidence of precursory electromagnetic signals of any type; further study showed that earthquakes with magnitudes less than 5 do not produce significant transient signals. The "International Commission on Earthquake Forecasting for