Department of Epidemiology & Public Health
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Maps & Directions
What Do We Mean by Disaster?
Definitions of disaster have been offered from multiple sources:
Drawing from these definitions, disasters possess the following common characteristics:
1) Extraordinary magnitude of harm
2) Ecological disruption
3) Disproportionate impact on vulnerable communities
4) Demands for response that exceed the community’s ability to cope
5) Necessity for outside assistance
Physical damage and destruction are hallmarks of many disasters, but not all. Disease pandemics, bioterrorism, cyberterrorism, and some incidents involving the release of a hazardous chemical or radiation may create notable disaster events without damage to physical structures.
The Demand/Capacity Equation
One salient element common to each of the preceding disaster definitions is the imbalance between the demands of the disaster event and the capacities of the affected community to respond. This has led disaster experts to propose a hierarchy of terms to describe critical incidents: emergency, disaster, and catastrophe (Quarantelli, 2006). To this list, we add the term “crisis”:
Natural disasters. The Centre for Research on the Epidemiology of Disasters (CRED), located in Brussels , Belgium , maintains the official international disaster registry. Whenever a disaster occurs anywhere in the globe, the event is reported to CRED and logged into the disaster database. CRED classifies natural disasters (“acts of nature”) into four subcategories: hydro-meteorological, geophysical, droughts and related disasters, and pandemics.
Human-generated disasters subsume various forms of “technological” disasters. Failures of human technologies are rarely intentional. However, poor judgment or human neglect may be precipitating or contributory factors. CRED classifies human-generated events into transportation, industrial, or miscellaneous accidents and ecological/environmental events.
We further subdivide human-generated disasters into non-intentional and intentional events (Shultz et al., 2006; 2007a,b). Intentional acts of “mass violence” routinely occur as an outcome of acts of terrorism, declared war, civil strife and ethnic conflict; and may also eventuate from mass gatherings and demonstrations.
Complex emergencies and global catastrophes. Some disasters defy facile classification into the categories presented above based on their scope, duration and capacity for producing humanitarian crises or threats to global security and survival on a grand scale. Complex emergencies are multi-dimensional events of long duration, frequently spawned by intentional, human-generated events such as war and civil strife. According to the World Health Organization and United Nations, a complex emergency is “a humanitarian crisis in a country, region or society where there is considerable breakdown of authority resulting from internal or external conflict which requires an international response that goes beyond the mandate or capacity of any single agency…complex emergencies are typically characterized by: Excessive violence and loss of life; massive displacements of people; widespread damage to societies and economies; the need for large-scale, multifaceted humanitarian assistance; the hindrance or prevention of humanitarian assistance by political and military constraints, and considerable security risks for humanitarian relief workers in some areas,” (UNDP, 2004). Global catastrophes endanger persons throughout the world and include scenarios such as precipitous global warming, global economic market collapse or massive planetary collision as well as extreme forms of events classified elsewhere such as a nuclear world war or highly virulent pandemic influenza.
* Photo courtesy of FEMA/Barry Bahler