Hypothetical Tsunami Scenarios and Evacuation Intention: A Case Study of Orange County, California

Abstract

Historically, California has had 14 tsunamis since 1812 where the heights of the waves were higher than three feet. One of California’s major tsunamis followed the 1964 Alaskan earthquake and caused 12 deaths, with damages totaling to at least 17 million dollars. According to Jose Borrero and Costas Synolakis in their report, “Tsunami Inundation Mapping, Field Survey Report and Final Recommendations for Orange County”, the worst case Tsunami scenario in Orange County, California, is a wave of approximately 10 meters or 32.81 feet (Tsunami Annex, 2009). Having evidence of historical tsunami events, even if not major ones, in addition to the probabilities of tsunami occurrences in the future requires the attention of both responsible administrative officials and the foundation of sound research directed toward planning for such events. The goal of this study is to measure how the surveyed population would respond in different, hypothetical tsunami scenarios should Orange County Officials advise the population to evacuate. The methodology consists of a survey of 235 people who live along the coastal area of Orange County, California. Method of Splitting Tsunami (MOST) model maps and GIS were used to delineate the evacuation and shadow evacuation zones in order to locate the spatial distribution of the population within these two zones. The results of this research indicated that the evacuation participation rate increases as the heights of the tsunami waves increase. The average socioeconomic characteristics of the sampled population vary from the sampled population when compared with the 2010 US Census data. This research may be useful for emergency managers, policy and decision makers.