Glendale (PDF) - Hazard Mitigation Web Portal - State of California
Glendale (PDF) - Hazard Mitigation Web Portal - State of California
Glendale (PDF) - Hazard Mitigation Web Portal - State of California
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Natural <strong>Hazard</strong>s <strong>Mitigation</strong> PlanCity <strong>of</strong> <strong>Glendale</strong>, <strong>California</strong>Section 6 – EarthquakesRisk AnalysisRisk analysis is the third phase <strong>of</strong> a hazard assessment. Risk analysis involves estimating thedamage and costs likely to be experienced in a geographic area over a period <strong>of</strong> time. Factorsincluded in assessing earthquake risk include population and property distribution in the hazard area,the frequency <strong>of</strong> earthquake events, landslide susceptibility, buildings, infrastructure, and disasterpreparedness <strong>of</strong> the region. This type <strong>of</strong> analysis can generate estimates <strong>of</strong> the damages to the regiondue to an earthquake event in a specific location. FEMA's s<strong>of</strong>tware program, HAZUS, usesmathematical formulas and information about building stock, local geology and the location and size<strong>of</strong> potential earthquakes, economic data, and other information to estimate losses from a potentialearthquake. A HAZUS loss estimation was conducted for the city <strong>of</strong> <strong>Glendale</strong> as part <strong>of</strong> its SafetyElement <strong>of</strong> the General Plan. That section <strong>of</strong> the Safety Element is reproduced in the followingpages.HAZUS-99 TM is a standardized methodology for earthquake loss estimation based on a geographicinformation system (GIS). A project <strong>of</strong> the National Institute <strong>of</strong> Building Sciences, funded by theFederal Emergency Management Agency (FEMA), it is a powerful advance in mitigation strategies.The HAZUS project developed guidelines and procedures to make standardized earthquake lossestimates at a regional scale. With standardization, estimates can be compared from region toregion. HAZUS is designed for use by state, regional and local governments in planning forearthquake loss mitigation, emergency preparedness, response and recovery. HAZUS addressesnearly all aspects <strong>of</strong> the built environment, and many different types <strong>of</strong> losses. The methodology hasbeen tested against the experience <strong>of</strong> several past earthquakes, and against the judgment <strong>of</strong> experts.Subject to several limitations noted below, HAZUS can produce results that are valid for theintended purposes.Loss estimation is an invaluable tool, but must be used with discretion. Loss estimation analyzescasualties, damage and economic loss in great detail. It produces seemingly precise numbers that canbe easily misinterpreted. Loss estimation's results, for example, may cite 4,054 left homeless by ascenario earthquake. This is best interpreted by its magnitude. That is, an event that leaves 4,000people homeless is clearly more manageable than an event causing 40,000 homeless people; and anevent that leaves 400,000 homeless would overwhelm a community's resources. However, anotherloss estimation that predicts 7,000 people homeless should probably be considered equivalent to the4,054 result. Because HAZUS results make use <strong>of</strong> a great number <strong>of</strong> parameters and data <strong>of</strong> varyingaccuracy and completeness, it is not possible to assign quantitative error bars. Although thenumbers should not be taken at face value, they are not rounded or edited because detailed evaluation<strong>of</strong> individual components <strong>of</strong> the disaster can help mitigation agencies ensure that they haveconsidered all the important options.The more community-specific the data that are input to HAZUS, the more reliable the lossestimation. HAZUS provides defaults for all required information. These are based on bestavailablescientific, engineering, census and economic knowledge. The loss estimations in this reporthave been tailored to <strong>Glendale</strong> by using a map <strong>of</strong> soil types for the City. HAZUS relies on 1990Census data, but for the purposes <strong>of</strong> this study, we replaced the population by census tract data thatcame with the s<strong>of</strong>tware with the 2000 Census data. Other modifications made to the data set beforerunning the analyses include:• updated the database <strong>of</strong> critical facilities, including the number and location <strong>of</strong> the fire andpolice stations in the City,• revised the number <strong>of</strong> beds available in the three major hospitals in <strong>Glendale</strong> to betterrepresent their current patient capacity, and2006 PAGE 6 - 35