Population Exposure and Impacts from Earthquakes: Assessing Spatio-temporal Changes in the XX Century
S. Freire, D. Ehrlich and S. Ferri

doi:10.3970/cmes.2015.109.159
Source CMES: Computer Modeling in Engineering & Sciences, Vol. 109, No. 2, pp. 159-182, 2015
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Keywords Population distribution; exposure; earthquakes; spatio-temporal analysis; megacities.
Abstract

Media and specialized scientific literature are often addressing the “increasing impact and ensuing damages due to natural hazards”. It is frequently argued that a rising frequency and intensity of hazards is responsible for the increase in losses. The role of increasing population exposure due to phenomenal population growth, or urbanization as a driver of risk is still insufficiently addressed. We investigate spatio-temporal changes in population exposure to seismic hazard and their role on impacts from earthquakes in the XX century. Spatial analysis is used to study historical population distributions in relation to seismic intensity, at the global and continental levels. Changes in number of victims were also analyzed, while considering the progress in frequency and magnitude of hazard events. There is also a focus on megacities and implications of fast urbanization for exposure and risk. We find that global population exposure in zones of severe seismic hazard has grown above overall population growth rates, with exposure growth rates being highest in the Americas, Asia, and Oceania. Results illustrate the relevance of population growth and exposure for risk assessment and disaster outcome, and underline the need for conducting detailed global mapping of settlements and population distribution.

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