Trends in the casualty ratio of injured to fatalities in earthquakes

Abstract

The worldwide ratio of injured to fatalities in earthquakes, R = Inj/Fat, has increased over time. This shows that it is more likely by approximately a factor of 2 that a person survives an earthquake today than 50 years ago. However, any meaningful analysis of R requires (as a minimum) separation by type of country and by location of epicentres (land or offshore). R in earthquakes beneath land is typically half of that for events offshore. R in the industrialised world is about two to three times larger than in the developing world. The countries that have made the greatest progress in protecting their population are Japan and China. Countries where R has not increased with time include Iran, Turkey, and Greece. The basic trends are clear, but the data sets for some individual countries are too small for the averages to be considered firm. We propose to use R to adjust the casualty matrices for estimation of human losses due to earthquakes worldwide.