GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 91-7
Presentation Time: 9:55 AM


WEST, Dixie Lee, Biodiversity Institute and Natural History Museum, The University of Kansas, Dyche Hall, 1345 Jayhawk Blvd, Lawrence, KS 66045, MACINNES, Breanyn, Department of Geological Sciences, Central Washington University, 400 E University Way, Ellensburg, WA 98926, GRISWOLD, Frances, USGS Pacific Coastal and Marine Science Center, 400 Natural Bridges Drive, Santa Cruz, CA 95064, NICOLAYSEN, Kirsten, Department of Geology, Whitman College, Walla Walla, WA 99362, HATFIELD, Virginia, Biodiversity Institute, University of Kansas, Lawrence, KS 66045, SAVINETSKY, Arkady, Laboratory of Historical Ecology, Russian Academy of Sciences, Severtsov Institute of Ecology and Evolution, Leninsky pr 33, 119071, Russia and OKUNO, Mitsuru, Department of Earth System Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku,, Fukuoka, 814-0180, Japan,

An international team of archaeologists, geologists, ecologists, and zoologists are conducting a comprehensive, interdisciplinary three-year (2014-2016) investigation in the little studied Islands of the Four Mountains, Alaska. That such research has not already occurred is understandable. The same volcanic activity, precipitous coastlines, high winds, and strong currents that posed profound risks to prehistoric individuals hinder modern research expeditions. Project goals include testing and documenting: a) interactions among human groups who peopled the North Pacific, b) long-term change in Holocene environments and consequent variations in terrestrial and marine animal populations and diversity and, c) human coping mechanisms and resilience in the face of potentially slow climatic and potentially catastrophic geological forces. The Islands of the Four Mountains region embodies environmental instabilities that, in the last 10,000 years, include changing subarctic climate, volcanic eruptions, earthquakes, tsunamis, and sea level fluctuations. Siting of prehistoric villages is one datum of human choice in the face of these instabilities. Villages in the Islands of the Four Mountains primarily set atop cliffs of eroding debris flow and tephra deposits; nearby lava flows enhance or create coves below village sites. Because lower, protected sites are available at Applegate Cove and Concord Point on Chuginadak Island, one question is why did prehistoric maritime peoples sometimes choose locations that were less accessible to the shore? An analysis of the log strand line near one Pacific-side site indicates that the AD 1957 tsunami, created by an earthquake on the Alaska-Aleutian subduction zone potentially as large as Mw 8.9-9.0, reached 18m above mean sea level at this location. Five of the six sites investigated face the Bering Sea rather than the Pacific, arguably more prone to tsunamis. Moreover, each of the village site is located higher than the 18m tsunami run-up height documents for the AD 1957 event. Assessing the degree to which environmental change and geological hazards in the Aleutians archipelago disrupted prehistoric human and ecological systems has important lessons for current inhabitants of the North Pacific Rim.