Epidemiological activities during a disaster include disease control and surveillance as well as injury epidemiology. Geographic Information System (GIS) information is now routinely used, ideally to detect disease clusters in real time. Prior to a disaster, epidemiological information is indispensable for the identification of vulnerable populations, with the use of mathematical and statistical risk models to identify areas that are vulnerable to natural disaster impacts, providing the basis for GIS map production (see Chapter 7). The U.S. Geological Survey already maintains a series of maps that depict earthquake risk as part of the National Seismic Hazard Mapping Project.1 These maps are available down to the zip code level throughout the United States. Population density maps can be overlaid on hazard maps to analyze the spatial concurrence of earthquake risk and population location. Many other countries with high levels of seismic risk have similar programs. Virtually any earthquake that has caused significant damage to human habitat has represented a potential public health problem because of the coincidence of risk and population distribution.
Vulnerability to both short- and long-term health effects is greatest among the impoverished and in the poorer parts of the world. One estimate is that the 66% of the world’s population living in the poorest countries accounts for 95% of the mortality due to disasters (Anderson, 1991). The immediate consequences are usually injuries or deaths due to trauma. Earthquakes cause trauma due to the collapse of structures and other edifices, and can also cause coastal flooding due to tsunamis. The recent 2004 Sumatran earthquake and tsunami caused drowning, traumatic injury, and structural collapse over a huge area around the Indian Ocean. A recent case control study in Taipei, Taiwan, suggests that socioeconomic status, preexisting health status, physical disability, and location were major predictors of mortality in the 1999 Chi-Chi earthquake (Chou et al., 2004).
Mitigation of the adverse impacts of future hazards necessitates their clear recognition, prediction, and early warning; quantification of the processes involved; accurate assessment of associated risks; and hazard avoidance or technological mitigation to reduce vulnerability. The first three steps require scientific and engineering investigations as well as an understanding of the social and population dynamics associated with hazards. The fourth component involves preventative measures such as redesigning and reinforcing buildings, bridges, and dams, and constructing all-weather shelters, dikes, and seawalls. This may also involve strength-