ICAR Research Data Repository for Knowledge Management

This study investigated societal response to a earthquake "predictions" issued for the San Francisco Bay Area in the aftermath of the 1989 Loma Prieta Earthquake. After 1989 earthquake, the Working group on California Earthquake Probabilities issued a report indicating the total 30 year probability of one or more earthquakes in the Bay Area was set at 67%.

As a result there was a desire to find an effective way to inform citizens. A document was prepared to appear in a Sunday edition of Bay Area newspapers. This document, titled "The Next Big Earthquake in the Bay Area May Come Sooner Than You Think" was distributed in several languages on September 9, 1990.

This study was designed to measure the impact of this document and what people thought and did to get ready for the next big earthquake. The study also sought to understand any negative economic or societal impacts resulting from the prediction of a major earthquake.

Data was gathered from the general public; businesses and corporations; health, safety and welfare organizations; and government agencies at the city, county, state and federal level. Eight counties in the San Francisco Bay Area were selected to represent the population at risk, including, Contra Costa, Alameda, Sonoma, San Francisco, Marin, San Mateo, Santa Clara, and Santa Cruz.

A total of 1309 questionnaires were mailed to households and a total of 806 usable questionnaires were returned, for a 61.6% response rate. Respondents answered questions on the effectiveness of the newspaper insert, what they remembered about the information provided in the insert, what they did to prepare for a future earthquake, reasons for not doing more preparation, and amount of perceived risk.