2024-018 - Emergency Operations Plan

Home Browse Search

City of Santa Ana Emergency Operations Plan Part I Basic Plan 2.4.1 Earthquake Earthquakes are considered a major threat to the City of Santa Ana due to the proximity of several major fault zones, notably including the San Andreas and the Newport -Inglewood Faults. A significant earthquake along a major fault could cause substantial casualties; extensive damage to buildings, roads and bridges; fires and gas leaks; and other threats to life and property. These effects could be aggravated by aftershocks and by secondary effects such as loss of water supply, power outages, hazardous materials spills or dam failure. A major earthquake could be catastrophic in its effect on the population, and could exceed the capabilities of the City, surrounding communities, Orange County, and even the State to respond. Extensive federal assistance could be required and could remain necessary for an extended period of time. Following major earthquakes, extensive search and rescue operations may be required to assist trapped or injured persons. Emergency medical care, food and temporary shelter would be required for injured or displaced persons. Efforts would be required to remove debris and clear roadways; to demolish unsafe structures; and to assist in reestablishing public services and utilities. In the event of a truly catastrophic earthquake, identification and removal of the deceased may pose a problem. Emergency operations could be seriously hampered by the loss of communications and damage to transportation routes within, to and out of the disaster area and by the disruption of public utilities and services. Some evacuations may be necessary from specific hazards (dam failures or hazardous materials spills), and some residents may self -evacuate if homes are damaged, utilities are out or critical resources (food, groceries, medical care) are unavailable, but large-scale or mass evacuation would be unlikely, especially if transportation routes are damaged or unsafe. Many families could be separated, particularly if the earthquake occurs during work and school hours, and continuing mass care and shelter for affected populations may be required for an extended time. In general, the population is less at risk during non -work hours as wood -frame homes are relatively less vulnerable to major structural damage than many commercial and industrial buildings. Transportation problems are intensified if an earthquake occurs during work hours, as significant numbers of residents commute for work or school to and from neighboring cities and counties. An earthquake occurring during work and school hours would create major transportation problems for those displaced persons. Hazardous materials spills could present a major problem in an earthquake. Orange County, one of the largest industrial and manufacturing areas in the state, has several thousand firms that handle hazardous materials, with several hundred firms handling materials rated as extremely hazardous and several dozen handling threatening levels of radioactive materials. These businesses are estimated to produce more than 100 million gallons of hazardous waste per year. City freeways, roadways and railways serve as hazardous materials transportation corridors, and Interstate 5 is the third busiest freeway corridor in the country. The City of Santa Ana represents not only the seat of government for Orange County, but also a transportation hub and primary location for business and industry in the county. The economic impact of a major earthquake on the City would be considerable in terms of the losses to the employment and tax base, affecting the ability of residents, businesses and government to make purchases and payments. History of Earthquake Events in Southern California Historical and geological records show that California has a long history of seismic events. The earliest recorded earthquake in California occurred in Orange County in 1769 on the San Joaquin Hills Fault. Southern California is probably best known for the San Andreas Fault, a fault running from near the Mexican border to a point offshore, north of the San Francisco Bay Area. Geologic studies show that over the past 1,500 years large earthquakes have occurred at about 140-150 year intervals on the Southern San Andreas Fault. As the last large earthquake on the Southern San Andreas occurred in 1857 (more than 160 years ago), that section of the fault is considered a likely location for an earthquake within the next few decades, according to www.data.scec.orw. 33