Informing citizens, local governments and business organizations about the earthquake hazard to increase awareness, mitigation and preparedness activities is a central element of the national effort to reduce earthquake losses. Relatively little research has been performed on organizational and public response to earthquake risk information about a specific likely future event, since few actual earthquake predictions, advisories, forecasts (they go by many names) that are scientifically credible have emerged in the United States. This research is a study of public and organizational response in the complex, urban, multi-county San Francisco Bay Area to the communication of risk information about that area's next major earthquake. Qualitative and quantitative research will be performed. Mail questionnaires will collect relevant data on a statistically representative sample of households. Interviews will be conducted with key informants from purposefully selected local and non-local businesses, government and other health, safety and welfare organizations. The opportunity to study public and organizational response to scientifically credible risk information about a future major quake in a complex urban setting is rare. This research will describe the effects of the dissemination of such information, and test a set of integrated hypothesized explanations for what is observed.