Earthquakes and tsunami as elements of environmental disturbance on the Northwest Coast of North America

Archaeologists have long speculated on the effects of large magnitude geological and atmospheric events on ancient peoples. This is particularly true on the southern Northwest Coast of North America, where approximately every 500 years the region experiences large earthquakes, tsunami, and coastal subsidence. The immediate impacts of these events on indigenous communities are relatively easy to predict-some destruction of settlements through ground shaking and tsunami flooding is likely. However, because no large magnitude earthquakes have struck here since Euro-american contact, no direct modem analogs exist for assessing longer-term impacts to coastal environments and in turn affects on indigenous subsistence economies. Explored here are environmental and landscape changes associated with earthquakes and tsunami on the Northwest Coast. For this, environmental and landscape changes associated with the 1964 Alaskan earthquake, ecological impacts of earthquakes in other regions, and life-histories of utilized species are examined. It is argued that while these events were significant disturbances to ecosystems, in most cases ecological recovery would be fairly rapid. Some disturbances eventually might have had positive outcomes in terms of human subsistence. As such, earthquakes and tsunami should not necessarily be viewed as ecological disasters but rather as large magnitude disturbances that presented challenges and hazards to native peoples. (c) 2005 Elsevier Inc. All rights reserved.