ROBIN TORRENCE AND JOHN GRATTAN
In a landmark book which examined the role of volcanic eruptions in human evolution, Sheets and Grayson (1979:6) could legitimately note that very few archaeologists had paid significant attention to the potential cultural effects of the natural hazards (e.g. volcanic tephra, earthquake-damaged walls, etc.) whose occurrences were apparent from many of their excavations. The current situation is radically different. In recent years studies stressing the impacts of past natural disasters on ancient societies have increased dramatically, although the majority of these are still authored or inspired by natural scientists and astronomers rather than archaeologists (e.g. Ambrose, 1998; Driessen and Macdonald, 1997; Harris, 2000; Isaacson and Zeidler, 1999; McGuire et al., 2000; McCoy and Heiken, 2000; Newhall et al., 2000; Nur and Cline, 2000; Peiser et al., 1998; Siebe et al., 1996; Stiros and Jones, 1996). Volcanic eruptions have led the way as the most commonly invoked environmental forcing mechanism, but droughts, floods and earthquakes are now also regularly proposed as triggering cultural change.
If we look to the modern world as a model for what we might expect to find in the past, we find that severe climatic events that wreak havoc on human communities, destroy homes and livelihoods, and inflict high levels of mortality are surprisingly frequent and widespread. For instance, Tobin and Montz (1997) provide a graphic catalogue of disasters during the single typical year of 1985.
An earthquake in Mexico killed 20,000 people; a tropical cyclone killed 11,000 in Bangladesh, and one in Vietnam killed 670; 300 died from landslides in the Philippines; a volcano erupted in Colombia killing 25,000; a flood in China added 500 to the death toll; a storm in Algeria killed 26; cold waves were responsible for 290 deaths in India and 145 in the United States; a heat wave killed 103 in the United States; and 52 died in Egypt in a fire.
(Tobin and Montz, 1997:1)
A detailed study by Glickman et al. (1992) found that between 1945 and 1986,