From Yardstick to Gyroscope -
Interdisciplinary Methods for the Long-Term Study of Social-Ecological Systems
Natural & Unnatural Disasters: Assessing risk, vulnerability, and adaptability
Instructor - Anthony Oliver-Smith
Date - April 14

Wisner, B., P. Blakie, et al. (2004). At Risk: Natural Hazards, People's Vulnerability and Disasters (The Disaster Pressure and Release Model). New York, Rutledge. Publication

In evaluating disaster risk, the social production of vulnerability needs to considered with at least the same degree of importance that is devoted to understanding and addressing natural hazards. Our view is that the risk faced by people must be seen as a cross-cutting combination of vulnerability and hazard. Disaster are a result of the interaction of both; there cannot be a disaster if there are hazards but vulnerability is (theoretically) nil, or if there is a vulnerable population but no hazard event.

"Hazard" refers to the natural events that may affect different places singly or in combination at different times. What we are arguing is that the risk of disaster is a compound function of the natural hazard and the number of people, characterized by their varying degrees of vulnerability to that specific hazard, who occupy the space and time of exposure to the hazard event. There are three elements here: risk (disaster), vulnerability, and hazard.

The Pressure and Release model (PAR model) is introduced as a simple tool for showing how disasters occur when natural hazards affect vulnerable people. The "pressure" idea is that a disaster is the intersection of two opposing forces: those processes generating vulnerability on one side, and the natural hazard event (or sometimes a slowly unfolding natural process) on the other. The "release" idea is incorporated to conceptualize the reduction of disaster: to relieve the pressure, vulnerability has to be reduced.