Disasters are social phenomena. Although they are initially caused by either natural or human activities, the required condition for a disaster is the existence of victims: i.e. there must be direct or indirect damage sustained by humans. When no one suffers a loss, then we are dealing solely with a natural phenomenon. The nature and extent of the damage results from the interactions among the type and severity of the initiating event, local conditions, and the specific cultural context.
Tsunamis represent a rare, rapid-onset phenomenon, which present a hazard in many coastal areas of the world, in particular all areas of the Pacific, the Mediterranean basin, and in rare extreme cases the North Atlantic and the North Sea. The study of recent tsunami events, their impact and the subsequent communal response is vital if archaeologists are to construct robust paradigms by which to interpret and understand the influences that tsunamis may wield upon cultural development.
A tsunami is a rhythmic movement of the sea that originates in any displacement of the sea floor. The movement of the sea floor, whether up or down, displaces the water column above that point. Waves then radiate out in all directions from the place where the water column was disturbed. These waves differ from normal ocean waves in that the entire water column moves, from sea floor to surface, whereas normal wind-driven waves and ocean swells affect only the top layer of the ocean. In deep water the tsunami travels imperceptibly, with low amplitude, long wave length, and high speed. Only when the tsunami reaches shallow water do the waves slow down and become higher and steeper. When the tsunami reaches the coast, it is likely to be travelling at 10-15 m per second (35-50 km per hour).......
