Public Perception of Relative Risk: Earthquakes vs. Hurricanes in the San Diego Region

Abstract:

Public perception of risk is key in pre-disaster preparation. Despite admonitions from emergency planners, people often fail to take reasonable precautions. But if emergency planners also fail to realize the possibility of a particular disaster scenario, there is very little chance that the public will plan for it. In Southern California there is a well-known risk associated with earthquakes, and it would be difficult to find anyone that didn't understand that the region was subject to risk from earthquakes. On the other hand, few, if any people consider the risk associated with tropical storms or hurricanes. This is reasonable considering people have always been told that the west coast of the United States is immune from hurricanes due to the cold water associated with the California Current, and the hazard of earthquakes is fairly obvious to anyone that has lived the for a while. Such an attitude is probably justifiable for most of Southern California, but it's unclear whether this is true for the San Diego region: destructive earthquakes are historically rare, and there is good evidence that the region was affected by a Category 1 hurricane in 1858. Indeed, during the last 70 years, more people have died from tropical cyclones in Calfornia's southernmost counties (San Diego and Imperial) than have died from earthquakes. In this paper we compare the relative risks from these two different types of disasters for the San Diego region, and attempt to answer why one type of hazard is emphasized in public planning and the other is neglected.