A GIS-Based Assessment of Earthquake Property Damage and Casualty Risk: Salt Lake County, Utah

This paper offers a probabilistic assessment of expected property damage and casualty risk due to the earthquake ground shaking hazard affecting Salt Lake County, Utah (population = 725,600). Salt Lake County is bisected by a segment of the Wasatch Fault. It is also at risk from twenty-one other nearby fault segments. Findings are based on (1) a microzonation of the earthquake ground shaking hazard, (2) an inventory of buildings by value, structural frame type and use, (3) earthquake damage functions defining the performance of buildings as a function of ground shaking intensity, (4) data on the density of residential and employee populations, and (5) earthquake casualty functions defining casualty risk as a function of building damage. The analysis is supported by the algebraic combination of digital map layers within a vector-based geographic information system. Triangular irregular network models show the expected distributions of casualties. Hazard mitigation policy implications are also considered.