The mitigation of natural hazards requires an understanding of how risk is distributed, both geographically and socially. Fundamental to this is the notion that aspects of risk are socially constructed, and therefore this paper explores the subject from both data and conceptual perspectives. These risk patterns evolve over time due to the changing structure of social-economic, demographic and constructed systems, and also due to changes in the physical environment. Risk must therefore be viewed as a constantly changing dynamic system. A review of the literature suggests that risk is increasing in some very significant ways, and that mitigation strategies should pay close attention to those trends if they are to be effective.