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2021 Multijurisdictional Local Hazard Mitigation Plan There are 26 bridges in San Mateo County with exposure to the landslide hazard. Landslides can knock out bridge abutments or weaken the soil supporting a bridge, obstructing the bridge or making it hazardous for use. Bridges in areas of high landslide risk often provide the only ingress and egress to large areas. 12.3.3 Environment All natural areas within the high susceptibility zones for landslide are considered to be exposed to the hazard. 12.4 VULNERABILITY Vulnerability estimates for the landslide hazard are described qualitatively. No loss estimation of these facilities was performed because damage functions have not been established for the landslide hazard. 12.4.1 Population All people exposed to the landslide hazard are potentially vulnerable to landslide impacts. Populations with access and functional needs as well as elderly populations and the very young are more vulnerable to the landslide hazards as they may not be able to evacuate quickly enough to avoid the impacts of a landslide. To apply an equity lens to this assessment, an analysis was performed using the SoVI ratings (see Section 7.2.2) of the population living in high or very high landslide susceptibility zones. Detailed results by jurisdiction are in Appendix E. Table 12-3 summarizes results for the overall planning area. Table 12-3. Distribution of Population Exposed to Landslide Hazard by SoVI Rating SoVI Rating Population Living in Exposed Areas Having the SoVI Rating Shown Number of People % of Total Exposed Population Very High 49,222 25.84% Relatively High 48,485 25.46% Relatively Moderate 52,477 27.56% Relatively Low 19,557 10.27% Very Low 20,708 10.87% 12.4.2 Property Estimates of potential losses associated with landslides were developed representing 1 percent, 10 percent, 30 percent, and 50 percent of the replacement value of structures exposed to the landslide hazard. This allows emergency managers to assess potential economic impact based on assumptions about the percent of damage to the general building stock. Damage in excess of 50 percent is considered to be substantial by most building codes and typically requires total reconstruction of the structure. Table 12-4 shows potential losses in the areas with the highest degree of landslide susceptibility. 12-10