Chapter 1 - Hazard Mitigation Web Portal - State of California

State of California Multi‐Hazard Mitigation PlanChapter 5 – Earthquakes, Floods and Wildfires: Risks and StrategiesOther Caltrans transportation system mitigation actions include:• Highway Bridge Program to replace or rehabilitate public highway bridges over waterways,other highways or railroads when the State and Federal Highway Administration determinethat a bridge is significantly important and is unsafe because of structural deficiencies,physical deterioration or functional obsolescence. Approximately $240 million in federalfunds are made available to local agencies annually under the Transportation Equity Act forthe 21st Century (TEA21).• Culvert Inspection Program intended to preserve and upgrade the State’s investment inhighway drainage infrastructure. The inspections identify drainage and structuraldeficiencies to be addressed by major maintenance and capital rehabilitation/replacementcontracts.Ports and HarborsThere is no systematic integrated database or inventory on seismic hazard assessment ormitigation for ports and harbors in California. However, most of the large ports and harborshave initiated some sort of seismic hazard study for various projects in recent years.Ground deformation is a significant vulnerability in various ports and harbors since significantpiers and quays are built out of dredge tailings or fill. Landfills do not typically perform well inlarge earthquakes as evidenced by damage to man‐made ground in the Marina District of SanFrancisco and in Kobe, Japan. Ground deformation on landfills at ports and harbors can affectharbors and ports by changing the alignments of tracks for large cranes used to load or off loadcargo ships. Such deformation may occur from lateral spreading, liquefaction, dynamiccompaction, or secondary ground rupture. After the 1989 Loma Prieta Earthquake, some of theOakland Airport’s runways experienced severe ground deformation. This damage impactedairport operations.Depending on the location, geometry and depth of the port or harbor, it may be susceptible to atsunami or seiche. To date, California has had only one series of tsunamis that significantlydamaged a port or harbor. That event was a series of tsunamis that hit the Port of Crescent Cityafter the M9.2 earthquake in Alaska on March 26, 1964.The American Society of Civil Engineers has created Seismic Guidelines for Ports. The guidelinesprovide generalized information for assessing seismic hazards for use in developing seismichazard mitigation design criteria. The guidelines are based on observations of the performanceof ports and harbors after earthquakes around the world. Several ports and harbors have alsoconducted seismic hazard mitigation projects.Communication SystemsCalifornia has no seismic hazard inventory for its communication systems. However, there is aguideline for the improvement of performance during earthquakes titled Methods of AchievingImproved Seismic Performance of Communications Systems (Tang and Schiff, 1996).The greatest vulnerability of communication systems depends on what communications aspectsare under consideration. For example, strong ground shaking tends to affect switches and otheraboveground components more than liquefaction. The latter may affect below ground conduitsPublic Comment Draft – July 2010 176