Applying Earthquake Risk Analysis Techniques to Land Use Planning

Recently developed methods of risk analysis are capable of modeling variations in earthquake hazard and its resultant damage to urban development. This type of risk analysis can provide useful information for land use decisions. Our article describes a probabilistic approach to earthquake risk analysis, which begins by estimating and mapping the expected level of ground motion over a study area. Areas subject to the earthquake-induced secondary hazards of landsliding and liquefaction are identified and combined with ground motion to describe the overall hazard. Damage estimates (by type of structure) can be produced for either the existing land use pattern or alternative future scenarios; that information can be used to evaluate alternative land use patterns in terms of their potential for earthquake damage. To illustrate the approach we use a case study application of earthquake risk analysis techniques to an area in San Luis Obispo County, California. We summarize the reactions of several practicing planners to this method of earthquake risk assessment, and we discuss the implications of improved risk analysis techniques for land use planning.