Item 26 - Adoption of the City of Santa Ana Emergency Operations Plan

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City of Santa Ana Emergency Operations Plan Part I Basic Plan Figure 38 Liquefaction Damage Kobe, Japan Earthquake, 1995 T ',0 *.1 . ,0 ti '"0 �* i o. 4 0 r Landslides - Earthquake -induced landslides are secondary earthquake hazards that occur from ground shaking. They can destroy roads, buildings, utilities and other critical facilities necessary to respond to and recover from an earthquake. Orange County has many active landslide areas, and a large earthquake could trigger accelerated movement in these slide areas, in addition to jarring loose other unknown areas of landslide risk. The City of Santa Ana is primarily flat and not susceptible to landslide, with the exception of a few small areas along the Santiago Creek in the north of the City. However, landslides in other communities may disrupt utility, communications or transportation infrastructure critical to the City's needs. Tsunami and Seiche A tsunami is a powerful ocean wave caused by a seismic event that raises or lowers the sea floor, shifting a massive volume of seawater and causing a series of large or massive waves to sweep ashore. The City of Santa Ana is far enough from the coast that tsunami is not a threat. However, Orange County coastal cities are potentially at risk from tsunami, which could result in an influx of evacuees and traffic into the City. A seiche is a series of large waves, generated by seismic shaking, on an enclosed body of water such as a lake, pond, reservoir or large swimming pool, numerous of which exist in Santa Ana. Seiches may result in significant side -to -side sloshing of water, resulting in displacement of water onto the ground surface and causing localized flooding, damage to nearby structures, or damage to the structure of the lake, reservoir or pool. Earthquake Susceptibility and Damages The effects of earthquakes span a large area, and large earthquakes occurring in many parts of Southern California would probably be felt throughout Orange County. However, the degree to which the earthquakes are felt and the damages associated with them may vary. Earthquake damage occurs where humans have built structures that cannot withstand severe shaking. Homes, businesses, schools and lifelines (roadways and utility lines) suffer damage in earthquakes and cause death or injury to people. At risk from earthquake damage are large stocks of old buildings and bridges; high tech and hazardous materials facilities; extensive sewer, water, and natural gas pipelines; dams and reservoirs; fuel tanks and pipelines; and other critical facilities and private property. Addressing the reliability of buildings, critical facilities and infrastructure, and understanding the potential costs to government, businesses, and residents as a result of an earthquake, are challenges facing the City. 38