Determining acceptable seismic risk: A community participation-based approach

Earthquake events are natural hazards that are beyond the control of human beings. In that regard they are different from manmade hazards and other natural hazards. Major earthquake events are low probability, high consequence occurrences. Throughout the world these events have resulted in death tolls numbering in thousands and have caused economic losses of billions of dollars.; Significant recent earthquake events in California have demonstrated that indirect economic losses far exceed direct economic losses. Although, the federal government has aided communities in the past, the focus of funding for disaster assistance has recently changed to promoting the concept of partnership between local governments, residents and businesses. Communities have not dealt with natural hazard mitigation measures proactively in the past.; This study focuses on defining, determining and measuring acceptable seismic risk to a community through community based input. The study has six parts: social and cultural theories of risk, total seismic risk, acceptable seismic risk, stakeholder identification, preferences of experts as proxies for stakeholders and analysis of preferences through an Analytical Hierarchy Process (AHP).; Social and cultural theories of risk are found to be applicable to seismic risk. Total seismic risk is comprised of technological, economic and societal components. Due to limited resource capacity acceptable seismic risk to a community is less than the full impact of a seismic hazard. The impact can also be modified by stakeholders' actions.; Stakeholders are identified and their preferences on attributes of acceptable seismic risk are sought through questionnaires. Expert opinions as proxies for stakeholder preferences are utilized. Final weights for attributes are determined using the Analytical Hierarchy Process (AHP) methodology. Qualitative statements are converted into quantitative data using a conversion scale used in AHP.; It is posited that resource allocations can be made based upon final weights of attributes. The methodology developed is intended to be applicable to different levels of government. It is believed that input from the community leads to better decision-making in addressing public policy and resource allocations and promotes personal voluntary actions to mitigate seismic risk.