GEOLOGICAL HAZARDS, CLIMATE CHANGE, AND HUMAN/ECOSYSTEMS RESILIENCE IN THE ISLANDS OF THE FOUR MOUNTAINS, ALASKA

Fig. 1. Mt. Carlisle volcano as seen from Chuginadak Island. Photo by K. Nicolaysen

Project Director: Kirsten Nicolaysen (Whitman College)

Number of students: 3

Approximate dates: July 24 to August 20th

Project summaryAssessing the degree to which geological hazards in the Aleutian archipelago disrupted prehistoric human and ecological systems has important lessons for current inhabitants of the northern Pacific Rim. The Islands of 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. Compared to adjacent regions to the east and west, strong ocean currents and smaller island size magnify ecologically-driven resource extremes, perhaps creating a physical bottleneck and the cultural boundary among Unangan/Aleut peoples that persisted into the early 20th century. These islands provide an excellent opportunity to assess the development of prehistoric human adaptations to geological hazards and environmental change. The Four Mountain prehistoric sites are little studied but are highly significant in light of new geologic data indicating volcanic activity during human migration and societal development in the Aleutian archipelago. A team of professional and student archaeologists, geologists, ecologists, and zoologists will conduct a comprehensive, interdisciplinary three-year investigation in the Islands of the Four Mountains. New radiocarbon, geological, paleoenvironmental, and cultural data expected from these sites will yield novel insights into the record of geological hazards, human coping mechanisms, changing subsistence, and adaptations during the prehistoric and European contact periods.

Archaeological evidence indicates that the Aleutian Islands were first settled in the east circa 8500 years ago (Dumond and Knecht 2001; Laughlin 1963; McCartney 1984) with Aleuts expanding westward across the archipelago, and reaching the central Aleutians 6000-7000 years ago (Okuno et al. 2012; O’Leary 2001; Savinetsky et al. 2012) and the western islands 3500 years ago (Corbett et al. 2010; West et al. 1999). Volcanic in origin, the Aleutians divide the north Pacific and the Bering Sea and result from subduction, a tectonic setting prone to extremely large earthquakes with the potential to create devastating tsunamis. Nonetheless, the Aleutians are globally important because humans on two continents rely on fish from its marine ecosystem. Moreover, given the sensitivity of airplanes to volcanic ash and of coastal cities to tsunamis, its geologic hazards potentially affect all nations of the northern Pacific Rim. Comprehensive research on long-term human environmental interactions in the Bering Sea region, set against a backdrop of accelerated global change, is vital to understanding the dynamics of Aleutian biological and human systems and effectively addressing the social, political, and economic issues that arise from changes in those system dynamics today.

 Geologically and archaeologically, the Islands of the Four Mountains (IFM) group is a missing component from local and regional studies of the Aleutians. Separated from substantial prehistoric and historic settlements of the larger Fox (east) and Andreanof Islands (west) by Samalga and Amukta straits, seven small volcanic islands comprise the IFM: Amukta, Yunaska, Herbert, Carlisle, Chuginadak, Kagamil and Uliaga (Fig. 1). Little explored, they require comparable investigation with the modern, interdisciplinary research tools and methodologies that have been employed on other North Pacific island groups. Our goal is to investigate the geologic evidence for abrupt hazardous events such as eruptions, earthquakes and tsunamis and to integrate both sudden and gradual environmental changes (e.g., sea level changes) into the temporal record of subarctic human society (e.g., West et al. 2012).

The antiquity of western Aleutians occupation required that prehistoric humans transited through the Islands of the Four Mountains, although the timing of the initial establishment of IFM habitation is yet to be determined. Crossing Samalga Pass, a 40-km-wide strait, was, and remains, particularly formidable— 18th century Russian sailors recognized this waterway as circulating large ocean currents. Moreover, Samalga Pass and the Islands of Four Mountains mark a distinct geographic boundary between the eastern and central-western Aleutian archipelago that coincides with pre-contact linguistic and cultural boundaries (Ladd et al. 2005; Veltre 2012). In addition to geographic challenges, volcanic eruptions occurred during the period of migration and habitation (e.g., Pekar et al. 2005; Larson et al. 2007) though the geological record of eruptions and earthquakes is poorly investigated in this region.

The steep, conical morphology of Mt. Carlisle (1524 m elevation) and Mt. Cleveland (on Chuginadak) suggest substantial Holocene growth of these stratovolcanoes, and preliminary 14C dating of soils and grasses intercalated with tephras on the northern flank of Mt. Cleveland document that local eruptions occurred during the period of human occupation. Although Veniaminov and Grewingk documented witnessed IFM eruptions during Russian occupation (Black and Geoghegan 1984; Jaensch 2003), these accounts do not clarify which of the two volcanoes erupted. Also the current seismic record indicates the potential for catastrophic earthquakes to affect the IFM during prehistoric settlement. Three of the largest earthquakes ever recorded occurred on the Aleutian subduction zone (Johnson et al. 1994), and most of the subduction zone has ruptured historically (Wesson et al. 2007).  The 1957 (Mw 8.6) Andreanof Islands earthquake concentrated slip at the IFM (Johnson et al. 1994) likely caused co-seismic land-level change in the islands though this is undocumented. Paleoseismic sedimentary and geomorphological evidence of large Holocene earthquakes is little studied in the Aleutians, although such studies have been successful along the Alaska Peninsula (Begét et al. 2008; Fryer et al. 2004; Shennan et al. 2009) and preliminary exploration the sedimentary record on adjacent Umnak Island indicates tsunami deposits within the Holocene record (R.C. Witter, pers. comm.). Moreover, Begét et al. (2008) describe evidence that volcanic eruptions as well as large earthquakes have the potential to generate tsunamis in the Aleutian chain.

Figure 2. The Islands of the Four Mountains, Alaska, showing Carlisle and Chuginadak Islands in the study area. Yunaska and Amukta to the west not shown. Preliminary 14C dates show explosive eruptions in the IFM at circa 2700 and 3600 calib. yBP (Nicolaysen, unpublished data), synchronous with human movement westward to the central Aleutians (image from: NASA Earth Observatory, 2012).

Island habitation and geologic hazards. We will focus our investigation on Chuginadak and Carlisle Islands. The prevailing winds are westerly, thus prehistoric sites on Chuginadak are typically downwind of Mt. Cleveland volcano. Site distances from the volcano vary, allowing assessment of the hypothesis that closer prehistoric sites would be more greatly impacted by tephra deposition. The interplay between habitation and tephra deposition provides an outstanding opportunity to use high-resolution stratigraphy and 14C dating to investigate both the frequency of the volcano’s eruptions and the human response to this hazard. The results of the tephrochronology will anchor our investigation of human responses to other local, natural hazards. For example, some site locations are more susceptible to prehistoric seismogenic tsunamis than other sites, and the tephrochronology will enable temporally appropriate correlations.

The prehistoric eruption history of Mt. Carlisle volcano is entirely obscure. The southern flank of Carlisle exposes approximately a dozen tephra layers, yet neither the chronology, nor the source of these layers is established (Cooper 1991). It is possible they represent eruptions from Carlisle, Cleveland, or one or more of the caldera-forming eruptions of Herbert and Yunaska volcanoes. Prehistoric sites on Carlisle are usually upwind of Mt. Cleveland and thus possibly more protected from the eruption impacts. Also we will test the hypothesis that sites on Carlisle have diminished susceptibility to seismogenic tsunamis because Chuginadak and Herbert Islands stand between this volcano and the expected zones of shallow, large earthquake epicenters.

Island habitation and land area. The Islands of Four Mountains are considerably smaller compared to adjacent island groups (IFM: Carlisle <40km2; Chuginadak <170km2; Fox Islands include Unimak ~4,070, Umnak ~1770, Unalaska ~550km2; the Andreanof Islands: Atka, Adak, and Kanaga, ~1,050, 710, 370km2 respectively). Vegetation and animal species richness and consequent human foraging opportunities are correlated with island size (MacArthur and Wilson 1967; McCartney 1977). Given a smaller land surface, a hypothesis is that disturbances to the paleoenvironment, whether from geologic disasters or overconsumption of depleted biotic resources, would have a greater impact on human sustainability, requiring perhaps, innovative adaptations.

Clearly the combination of tephrachronology, detailed stratigraphy, 14C dating, and volcanic mapping included in this proposal will revolutionize our knowledge of volcanism in the IFM and its impact on human ecosystems. The different locations and different immediate volcanic threats of the proposed excavation sites provide an ideal opportunity to test fundamental hypotheses regarding how humans inhabiting the IFM responded to geologic hazards.

Project Research Plan

The Keck Consortium students will meet Professor Nicolaysen and other members of the research team in Anchorage AK. After an initial orientation day, we will fly to Dutch Harbor/Unalaska Village, Alaska, where we will attend presentations by all members of the research team at the Museum of the Aleutians. To facilitate comprehensive mapping and sampling as well as ensuring the safety of the research team, we have secured National Science Foundation funding for logistical ship and helicopter support for roundtrip transit from Dutch Harbor to the IFM and during the field season. The ship will transport the research team to the Islands of Four Mountains July 27th to 28th and field work will occur until approximately August 17th. Upon return to Unalaska Village and Dutch Harbor, students will aid the research team in archiving samples at the Museum of the Aleutians and shipping comparative lava and tephra samples for research to their home institutions. All artifactual materials will be archived at the Museum of the Aleutians or the Aleut Corporation headquarters. Before leaving Unalaska, students will write an introduction to their research project and proposed project plan to complete their research during the academic year.

Field Safety and Conditions

This project has a number of unusual field conditions and it is imperative that students understand that all of these may apply to our field season. The project co-directors (Dixie West, Kirsten Nicolaysen, Virginia Hatfield and Bre MacInnes) have had numerous conversations with the Alaska Volcano Observatory and with the NSF subcontractor CH2MHill Polar Services. The following information is based on the many years of sub-Arctic field experience of all the co- directors and on a comprehensive multi-page risk assessment performed independently by CH2MHill Polar Services, Inc., the support subcontractor hired by the National Science Foundation.

First, we will be working and living in remote conditions without regular telephone or internet access. Satellite phones and VHF radios will be used by all field teams. We will live both onboard ship (anticipated using the Research Vessel Maritime Maid) and camp on the islands of Carlisle and Chuginadak. After our plane flights to Anchorage and then Unalaska Island, we will embark on the ship for 1-2 days of transit time, depending on weather. For our access of the islands and research sites we will use both small Zodiac-style skiffs with outboard motors and a 6-passenger helicopter (Bell 407). The island camps will include living in a yurt and tents provided by CH2MHill Polar Services, Inc. Students will help assemble the tents and participate in the cooking/cleaning rotation. Students will also help with digging, maneuvering large screens for sieving soils, and carrying lava samples in packs weighing 20-35 pounds. The terrain is steep and rugged. Students should be able to hike distances of up to 5 miles (8 km) per day. Most work will take place between sea level and ~1,500 feet (460 m) elevations.  There are no bears on these islands. The presence of mosquitos and other biting insects is negligible, primarily because there is a lot of wind. Likely daytime temperatures will range from 45-75°F, but these temperatures combined with frequent rain and wind chill can cause hypothermia. I will provide a list of necessary equipment that will include non-cotton clothing (e.g., wool and/or polypropylene/capilene) as a must. Students will also need to acquire rubber boots and Goretex or similar waterproof jacket and pants. We will also need sunscreen, hats, and sunglasses as the entire spectrum of weather can occur.

 We will participate in safety briefings related to the ship, skiffs, and helicopters. Both emergency dry suits and Mustang work suits will be available for all participants.  Finally, Mt. Cleveland erupts periodically including in the past year (2013). Because of this, we will select our research sites and use the ship and helicopter resources with safety as our primary priority. We will also work closely with the Alaska Volcano Observatory staffpersons who participate in this expedition and follow completely their recommendations related to the volcano’s activity. The likelihood of a tsunami-inducing event during our field season is very small but not impossible.  Finally, Nicolaysen is a certified Wilderness First Responder (WiFR). If you have any first aid or wilderness first aid training, please indicate this in your application statement.

Potential student projects

All students will participate in archaeological excavation, which includes substantial digging and sieving, as well as participating in geologic mapping and sampling. Recommended coursework for each project is listed below, though some of these courses may be taken senior year concurrently with the research project.

Project 1: Site microstratigraphy- Reconstruction of the sequence of geologic events that impacted local habitation requires careful examination of the sedimentary microstratigraphy both within an excavated site impacted by humans and within a comparative geologic sequence nearby. This project will be most suited to students with preparatory coursework in Sedimentation and Stratigraphy, Geomorphology, Mineralogy, Volcanology (optional), and Paleoanthropology/Archeaology (optional).

Project 2: Provenance of lithic tools– The assemblage of tools recovered from the archaeological sites may show differences in what lavas were used for stone resources through time, as sites on other islands have demonstrated (e.g., Nicolaysen et al., 2012). This project will involve visual characterization of rock types used for lithic tools, non-destructive analysis of tools using a portable X-Ray Fluorescence spectroscoper (provided by Nicolaysen), and further analysis of micro-flakes in the discarded debitage of tool production. This project is most suited to students with preparatory coursework in Mineralogy, Petrology, and preferably Paleoanthropology/ Archeaology courses and/or Volcanology and Geochemistry (optional).

 Project 3: Geologic mapping of Carlisle Island– Understanding the acquisition and transportation of lava and tephra suitable for lithic tools recovered from archaeological sites requires mapping and sampling the available exposed geologic units on Carlisle Island. This student may also participate in mapping the lavas and tephras forming the older, eastern part of Chuginadak Island. This project will be most suited to students with preparatory coursework in Sedimentation and Stratigraphy, Geomorphology, Mineralogy, Petrology, and possibly Volcanology, Geochemistry, and/or Field Camp (optional).  Other potential projects include topics ranging from geomorphology of tsunami deposits, palynology and tephrochronology as discussed with other senior research scientists of the project team.

Project personnel

Prof. Kirsten Nicolaysen (Whitman College) will take primary responsibility for helping Keck project students define their research projects and complete their studies. Prof. Nicolaysen and colleagues have extensively studied Mt. Cleveland (Dean et al. 2004; Nicolaysen et al. 2003, 2005 and manuscripts in preparation; Pekar et al. 2003, 2005), and a preliminary geologic map is compiled. Nicolaysen has experience sourcing lithic artifacts and characterizing geologic sources and demonstrated that obsidian chips in archaeological sites on Adak Island were originally derived from obsidian deposits on Umnak Island approximately 650 km east of the sites (Nicolaysen et al. 2012).

Most unusually and excitingly, the students will benefit also from the experience in participating in a multi-national, multidisciplinary research team. Other project team members with geological expertise include Dr. Pavel Izbekov (University of Alaska, Fairbanks), Dr. Breanyn MacInnes (Central Washington University), and Dr. Mitsuru Okuno (Fukuoko and Nagoya Universities), as well as 2-3 additional research scientists with the Alaska Volcano Observatory. Dr. Izbekov will focus on determining the magnitude of volcanic eruptions and help complete geologic maps of Cleveland and Carlisle volcanoes. Dr. Breanyn MacInnes will lead the geomorphological and stratigraphic research components in the field and laboratory and has participated in similar paleoseismic studies in the Kuril Islands portion of Beringia (MacInnes et al. 2009, 2012; Pinegina et al. 2007). Data compiled by Dr. MacInnes and her M.Sc. student will be crucial to evaluation of seismic and tsunami hazards in the Four Mountains region. Dr. Mitsuru Okuno (Fukuoka University, Japan) will radiocarbon date and identify origins of volcanic tephras that intercalate archaeological sites. The tephrochronology is crucial to testing correlations between changes in the physical environment and the timing and pattern of human adaptations in the IFM (e.g., Okuno et al. 2012). Additionally there will be at least three archeologists (including co-PI’s Dixie West and Virginia Hatfield of the University of Kansas) and two paleoecologists participating in the field work. The students, funded jointly by the Keck consortium and an NSF grant to Nicolaysen, will interact with a coalition of project scientists as well as personnel of the Alaska Volcano Observatory, Museum of the Aleutians and members of the native Aleut and Ounalashka Corporations.

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http://eoimages.gsfc.nasa.gov/images/imagerecords/8000/8013/aleutians_ast_2007178_lrg.jpg

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Nicolaysen, K., T. Johnson, E. Wilmerding, V. Hatfield, D. West, and R. McGimsey, 2012. Provenance of Obsidian Fragments Recovered from Adak Island, Central Aleutian Islands: Evidence for Long Distance Transport of Raw Lithic Material. In The People Before: The Geology, Paleoecology and