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Chapter 9:Hazard Analysis—Tsunamis <br /> Coastal floodplain boundaries shown on the Flood Insurance Rate Maps (FIRM) for the <br /> County of Hawaii are based on the 100-year Tsunami: wave elevation; runup elevations; <br /> known topographic characteristics; and, a depth of flooding by the incoming Tsunami wave <br /> of 4.0 feet. The 100-year Tsunami inundation boundaries were delineated using methods <br /> outlined in "Tsunami Inundation Prediction," by C. L. Brentschneider and P. G. Wybro, <br /> which was presented at the 15`x' International Conference on Coastal Engineering, Honolulu, <br /> HI, in July 1976. <br /> Since Hilo has one of the most complete historical inundation mappings, this data was <br /> compared with the Preliminary DFIRMs to verify whether the VE zone encompassed the <br /> furthest inland inundation limits. Surprisingly, the VE underzoned the historical inundation <br /> (see Figure 9-11). <br /> FEMA and the County are currently working to improve the Preliminary DFIRMS for the <br /> County of Hawaii, which will include a careful evaluation of the coastal high hazard areas in <br /> terms of combining the most protective inundation area from FEMA's 2008 Hurricane Flood <br /> Study for Hawaii County(refer to Section 10.4.1.3) and the current effective FIRMs' coastal <br /> high hazard areas. <br /> Historical Inundation vs Evacuation Zone vs FIRM Legend <br /> Study Area:Hilo [=IHiston-I nundation Zone streets <br /> ®FIRM 100 Year Entire area in Tsunami Evacuation Zone <br /> Figure 9-11.Comparison of Historical Tsunami Inundation to FIRM VE Zone for Hilo <br /> 9-10 Hawaii County Multi-Hazard Mitigation Plan <br />