Sizes of Eruptions Count in the Ecuadorian Archaeological Record

Summary

This is an abstract from the "Celebrating the Contributions of Volcanologists Minard Hall and Patricia Mothes to Ecuadorian Archaeology" session, at the 90th annual meeting of the Society for American Archaeology.

Stratigraphic cuts at archaeological sites in the Northern Highlands or along the Coast, often display volcanic ash deposits, 10-30 cm thick, produced by large VEI 5-6 explosive eruptions in the Ecuadorian Sierra. Eruptions by Pululahua (2300 yBP), G. Pichincha (1000 yBP), Cotopaxi 1000 yBP and Quilotoa (800 yBP) pertain to this category. Eleven of these catastrophic mega eruptions occurred during the last 6000 years and involved dacitic or rhyolitic magmas. Modest-size eruptions (VEI 3-4) were more common, almost all of andesitic composition and whose ashes are scarce in distal areas. Cotopaxi leads the list with ~sixty eruptive layers in the past 6000 years; Cayambe with twenty; Tungurahua with ten following a sector collapse 3000 yBP; Antisana with fourteen and both the Cosanga Volcano Cluster and Chacana with five events each. For Reventador, Sangay and Sumaco volcanoes, the tally is incomplete due to high erosion rates leading to poor tephra preservation. The 125 eruptions is equivalent to an event about every 50 years. Given the high eruption frequency, we assume that early cultures had certain experience in dealing with volcanic phenomena. Future investigations should attempt to determine what were some adaptive strategies used by early cultures to successfully weather out eruptions.

This Resource is Part of the Following Collections

• Society for American Archaeology 90th Annual Meeting, Denver, CO (2025)   •
• Celebrating the Contributions of Volcanologists Minard Hall and Patricia Mothes to Ecuadorian Archaeology

Keywords

Record Identifiers

Abstract Id(s): 51179