Natural disasters—volcanoes, earthquakes, tidal waves—disrupt all or part of societies, provoking refugees, collapse of production and distribution systems, and intensified competition for resources. Man-made disasters (notably war) involve social causes as well as these consequences—with the implication that they are avoidable. So-called disaster research examines the social and psychological impact of these occurrences among those involved.
Some sociologists (most notably Robert Merton) have argued that disaster-sites offer important opportunities for sociological research and the construction of social theory, since the resulting conditions of collective stress compress social processes into an uncommonly brief time-span; make usually private behaviour public and therefore more amenable to study; and generally highlight aspects of social systems and processes that are normally obscured by the routine of everyday life. Research has established that disasters have typical phases (such as the warning, threat, impact, inventory, rescue, remedy, and recovery phases); that certain types of collective behaviour tend to be associated with each phase; and that the precise form taken by each phase is affected by the characteristics of previous stages. (Thus, for example, the scale of the remedy operation is in part a function of the degree of identification with the victims.) A good comprehensive account of this literature is G. W. Baker and D. W. Chapman's Man and Society in Disaster (1962), and a typical case-study is Kai Erikson's Everything in its Path (1976), which investigates the individual trauma (state of shock) and collective trauma (loss of communality) that followed a flood in previously tightly knit mountain communities in West Virginia.