This is a study of the location and demographic characteristics of households that have purchased earthquake insurance in California. The location of a sample of households with and without earthquake insurance for both northern and southern California will be compared with geologic characteristics (such as proximity to the San Andreas fault) to determine the existence of adverse selection. This portion of the study will utilize a major geographic information system to plot the location of 5000 or more households and compare them to geologic characteristics as well as census tract information. The second part of the study will involve a sample survey of households with and without insurance in order to ascertain the economic and demographic characteristics that differentiate these two populations. The two portions of the research will provide important baseline data upon which a better understanding of recent shifts in household-level decision-making with respect to earthquake insurance purchase will be obtained and will also provide information on which more enlightened policy can be based.