Guam Hazard Mitigation Plan - Western States Seismic Policy Council

SECTIONFIVERisk AssessmentBased on value of assets, exposure of the Essential Facilities is concentrated in Tamuning with 83facilities that are worth $520.3 million. The greatest concentration of Major Utilities is located inDededo, with 33 Major Utilities worth $25.4 million. Tamuning has 30 Transportation Systemsthat are exposed, worth $7.9 million. The village with the highest value of Transportation Systemsexposed is Piti, with 11 exposed assets worth $75.3 million.In terms of village-level GBS exposure, Dededo has the most exposure with 4,575 buildings,worth $729.7 million; followed by Yigo with 4,073 buildings, worth $373.7 million.Severe WindAs shown in Tables F-19 and F-20 (Appendix F [Vulnerability and Potential Loss Results byVillage]), areas exposed to extreme wind contain 81,753 people or 45.2 percent of Guam’spopulation. On a village level, 36,520 people in Dededo (72.8 percent of the village population)and 22,365 people in Yigo (98.4 percent of the village population) are exposed to extreme wind.The third highest village population exposed is Mangilao, with 6,022 exposed people (38.8percent of the village population). In addition, to Mangilao, more than 53 percent of thepopulation of Talofofo is exposed to extreme wind, as well as about 37 percent of the populationof Merizo.As noted in Section 5.5.2 (Most Significant Hazards Vulnerability Results), the exposure analysisused in this plan includes an assumption that the entire structure value is lost if an EFMUT orGBS is located in the hazard zone. In reality, many buildings and other assets exposed to severewind may not be completed destroyed; however, this assumption does provide a conservativeestimate of potential losses. Also, no contents values, loss of function costs, ordisplacement/temporary quarters costs are estimated for EFMUTS or GBS. (To address structureand contents damage, more data would be needed related to building age; building condition;construction types; structural connections; roof coverings; window and door type; and windowand door protection systems.)In reality, the functional ability of the commercial and essential facilities to respond after an eventis severely affected. Even if it was assumed that the infrastructure was not damaged and couldsupport an operations at these facilities, economic and social impacts will be significant. Afterrecent storms such as Super Typhoon Paka, Typhoon Chata’an, and Super Typhoon Pongsona,businesses and government operations took weeks to months to recover. This loss of function isoften the result of lost infrastructure; however, its effects are exacerbated by the inability toprevent wind and water intrusion within commercial and essential buildings.As mentioned earlier, although a structural failure of these types of buildings is devastating, it isnot common to see these types of failures from even these extreme winds. What is more commonis measurable structural damage combined with significant, if not total, loss of contents. Althoughthe cost of losing a structure to a typhoon is a real cost, to businesses, governments, and thepopulation, it is what occurs in those buildings that is needed to support the vitality of the socialand economic framework of the island.At the village level, as shown in Tables F-19 and F-20 (Appendix F [Vulnerability and PotentialLoss Results by Village]), Dededo and Tamuning have the highest quantity of Essential Facilitiesexposed to extreme wind, with 27 and 25 facilities, respectively. Dededo has the highest quantity(80) of Major Utilities worth $119.3 million that are exposed to severe wind. Piti has the highestquantity (9) of Transportation Systems worth $74.8 million exposed.5-68