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Chapter 7:Hazard Analysis—Earthquakes <br /> 7.3.1.3 Nonstructural Damage Assessment <br /> Surveys and possible incorporation into building codes must not be overlooked. <br /> 7.3.1.4 Susceptible Earthquake-Induced Ground Failure Areas <br /> More detailed maps based on soils are needed to identify earthquake-induced ground failure <br /> hazards such as liquefaction, landslide, and surface rupture. Liquefaction occurs when loose <br /> granular soils below the water table temporarily lose strength due to excess pore water <br /> pressure build-up during prolonged strong earthquake ground shaking. Accordingly, higher <br /> potential would tend to occur at sites with these subsurface characteristics in regions of <br /> higher seismicity, since events of Richter magnitude 6 or greater with EPGA of more than <br /> 0.1Og are generally necessary to induce liquefaction. There is further work needed to better <br /> define areas susceptible to liquefaction and landslides. Localized ground surface rupture may <br /> be found in closer proximity to the seismic source zone, but should not be viewed as <br /> extensions of subsurface seismic faults. <br /> 7.4 Risk Assessment <br /> Average Annualized Loss (AAL) of earthquake events is also computed using the HAZUS <br /> model. HAZUS computes losses for eight earthquake scenario events with different return <br /> periods: 100-year, 250-year, 500-year, 750-year, 1000-year, 1500-year, 2000-year, and 2500- <br /> year. <br /> Based on a HAZUS AAL analysis incorporating soil site factor mapping and Hawaii <br /> Construction Cost Data, earthquake AAL is about $65.1 million in Hawaii County. The <br /> predominant contributor to loss is the single-family residential construction. <br /> County Hawaii <br /> Earthquake AAL $65.1 million per year <br /> 7.5 Mitigation Strategies <br /> 7.5.1 Previous/Current Efforts <br /> As described in previous sections of this report, the design vintage can be used as an <br /> indicator of a buildings susceptibility to seismic damage. Seismic zonation under which the <br /> structure was designed and typical construction type (single or double wall) can be <br /> determined by the year built based on the corresponding version of the UBC or IBC in effect <br /> at the time. Table 7-2 and Table 7-3 provide statistics of the number of homes built under <br /> each version of the UBC, their design seismic zonation, and probable code compliance. Most <br /> existing homes are code deficient for seismic resistance. <br /> 7-18 Hawaii Countv Multi-Hazard Mitigation Plan <br />