Field Notes: The Polar Field Services Newsletter

Ancient adaptation and climate change in the Aleutian Islands

An aerial photo of the Islands of the Four Mountains. Photo: Ken Wilson, author of "The Aleutian Islands of AK: Living on the Edge"

An aerial photo of the Islands of the Four Mountains. Photo: Ken Wilson, author of “The Aleutian Islands of AK: Living on the Edge”

The Islands of the Four Mountains in Alaska’s central Aleutians are about as inhospitable an environment as a person can imagine. Bad weather reigns, the wind and rain conspiring to create the perfect conditions for hypothermia. Mount Cleveland, an active volcano on Chuginadak, erupts at regular intervals, and simply accessing the archipelago is an exercise in endurance.

Adaptation

All of this may explain why very little is known about the early settlers who crossed the Bering Strait and eventually made their way to North America. After entering Alaska some of these early inhabitants moved southward to the Alaska Peninsula and then westward, traveling through and occupying the Islands of the Four Mountains. As they adapted to their maritime world these people periodically faced natural disasters: tsunamis, volcanic eruptions, earthquakes, and changing climate and sea levels.

Surviving extreme weather and climate fluctuations

Understanding how these people adapted to their fluctuating environment is critical, informing both scientists and Pacific Rim communities how changing climate and periodic, large magnitude geologic hazards contribute to a changing physical world.

The changes are both gradual and continuous and punctuated by disaster; which played the larger role in affecting the prehistoric communities. This is why an international, collaborative research project is underway to uncover a breadth of information about the subarctic Islands of the Four Mountains. Starting this summer, Dixie West and Virginia Hatfield (Kansas University), Kirsten Nicolaysen (Whitman College) and Breanyn MacInnes (Central Washington University) will launch a three-year investigation with support from the National Science Foundation. The project includes excavating prehistoric village sites, studying volcanic eruptions and tsunamis, and determining climatic variations in the central Aleutians during the last 10,000 years.

“Our hypothesis is that the location and nature of the occupation sites [prehistoric villages] reflect the environment that the people were living in,” says Nicolaysen.

Fieldwork

To examine how the volcano might have affected these people, widely known as the Unangax^, the team selected village sites located at different distances and directions from Cleveland volcano. This summer’s field season will be devoted to excavating the sites and collecting a variety of stone, bone and volcanic ash samples. The village sites preserve critical scientific information about the ancient Unangax and the North Pacific region in which they lived.

Interdisciplinary collaboration

Specifically, the team will include archaeologists, geologists, ecologists, and zoologists. They’ll extract radiocarbon, geological, paleoenvironmental, and cultural data to understand how prehistoric communities adapted to geological hazards, changing climate, and interacted with humans living both to the east and west.  These data include chemical signatures from past volcanic eruptions, sediments from ancient tsunamis, analyses of peat bog deposits to determine climate change, and identification of shells and animal bones to investigate changes in hunting and collecting patterns over time.

“We know that Cleveland was active during the last 9,000 years, when people were making a crucial leap across Samalga Pass,” says Nicolaysen. “We’ll be investigating how much ash is covering the occupational sites; did the people change their pattern of collecting resources during natural disasters; did they abandon sites?”

Lessons for modern adaptation

“We want to study sea level when historic people were settling the islands, as well as how they adapted to earthquakes, tsunamis, and eruptions,” says West. “This can provide information about coping skills in the face of geological and climatic perturbations useful to peoples living in the region today,” she says.

“We don’t know how often earthquakes and tsunamis occur there,” says MacInnes. “Yet if you do a hazard analysis, the Aleutian Islands are one of the most dangerous in terms of the ripple effect. People living on the Pacific Coast today should be very concerned about what’s happening there, and our research will fill in some of the gaps.”

She adds that by looking in low-lying regions next to the coast, she anticipates finding tsunami deposits that will indicate the natural disasters that happened over time and with what frequency and magnitude.

This, along with other information expected to emerge from the research, will help inform everything from future building to evaluation of existing infrastructure safety, says Nicolaysen.

Collaborators on the project include Pavel Izbekov of the University of Alaska, Arkady Savinetsky and Olga Krylovich of the Russian Academy of Sciences, Mitsuru Okuno of Fukuoka University, Japan, Susan Crockford of Pacific Identifications, Victoria, Canada, John Power of the Alaska Volcano Observatory, Zoya Johnson of the Museum of the Aleutians, Unalaska City, and the Aleut Corporation, Anchorage.  —Rachel Walker

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