Graduation Year


Date of Thesis Acceptance

Spring 5-13-2015

Major Department or Program



Kirsten Nicolaysen


The Islands of Four Mountains (IFM) are located in the central region of the Aleutian Archipelago, an island arc inhabited by native Unangax populations beginning in the Holocene. The volcanic activity of the Aleutian Islands posed a serious threat to the Unangax populations. The stratigraphy of two archaeological sites on the IFM provides evidence of human occupation truncated by episodic tephra deposits. Grain size analysis, loss-on-ignition, and micromorphology corroborate field interpretations of stratigraphy. Site stratigraphy reveals debris flow deposits excavated by the Unangax to build their homes, which were subsequently abandoned following the deposition of thin tephras. Debris flow deposits and rapid accumulation of thin interbeds of tephras and paleosols to greater than 20 cm caused abandonment of Unangax habitation sites. Continued reoccupation of sites after volcanogenic events points to the resilience of Unangax populations to their changing environment.

Page Count


Subject Headings

Four Mountains‚ Islands of (Alaska), Aleutian Islands (Alaska) -- Environmental conditions, Geology -- Alaska -- Islands of Four Mountains, Aleuts -- History, Volcanoes -- Environmental aspects -- Alaska, Volcanoes -- Alaska, Aleutian Islands (Alaska) -- Environmental conditions, Whitman College -- Dissertation collection 2015 -- Geology Department

Permanent URL

Document Type

Whitman Community Accessible Thesis

Terms of Use

If you have questions about permitted uses of this content, please contact the ARMINDA administrator



Rights Statement

Rights Statement

In Copyright. URI:
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).