• Urban stream management: interdisciplinary assessment of the Ship Creek fishery

      Krupa, Meagan B. (2009-05)
      The Lower Ship Creek Fishery in the city of Anchorage, Alaska is one of the state's most popular sport fisheries. After years of channelization and development, this social-ecological system (SES) continues to experience the effects of urbanization and is struggling to achieve robustness. I applied a robustness framework to the management of management this fishery because of its semi-engineered nature. This framework uses interdisciplinary methods to study the interrelationships between the fishery's socio-economic and ecological components. Robustness is more appropriate than resilience as an analytical framework because of the relative insensitivity of the engineered components to ecological feedbacks. On Lower Ship Creek, the engineered hatchery fish continue to thrive despite declining stream conditions. The robustness of this fishery contributes to the resilience of the city by increasing local food and recreation options and supporting a diverse set of businesses. To study the robustness of this SES in the context of the resilience of Anchorage, I first combined historical photos and existing Ship Creek data with research conducted on other streams to create an environmental history of the creek. This history then was used to describe how eras of urban development have altered the creek's ecosystem processes and created new ecological constraints related to 1) loss of wetlands and riparian vegetation; 2) erosion, pollution, and channelization; 3) loss of fish species; and 4) flow alteration and habitat loss. Using Lovecraft's (2008) typology, I proposed four plausible management scenarios that highlight the trade-offs associated with management of this fishery: 1) Ship Creek Redesign, 2) Mitigation, Construction, and Maintenance, 3) KAPP Dam Removal, and 4) Business as Usual. The second of these scenarios is most consistent with the current ecological constraints, the characteristics preferred by most stakeholders, and current socio-economic trends. Since Scenario 2 will require a large monetary investment, I examined this SES's cost structure and compared it with previously published analyses of the economic benefits of the fishery. By quantifying the costs borne by each agency, I showed how externalities produce intra- and inter-agency tension. These data were used to construct a new cost-sharing framework that provides decision makers with an economic incentive to work more cooperatively in the future. I then explored the interrelationship of the SES's socioeconomic and ecological subsystems, using Anderies et al.'s (2004) framework. I applied Ostrom's design principles (1990) to sport fisheries to explore the reasons why agencies have not cooperated to produce a more robust fishery. This SES fails to meet three of the design principles: it lacks 1) an equal proportion of benefits and costs, 2) collective-choice arrangements, and 3) user and biophysical monitoring. I then suggest how to improve the design and increase the robustness of this SES. This study proposes that the maintenance of semi-engineered systems is important both for local users and for the resilience of states and countries. In the context of global trends toward increasing urbanization, this study provides an interdisciplinary approach to increasing the robustness of urban streams and building resilience within states and countries.
    • Using infrasound to characterize volcanic emissions at Tolbachik, Karymsky, and Sakurajima volcanoes

      Albert, Sarah; Fee, David; Tape, Carl; Szuberla, Curt (2015-08)
      The work presented herein includes one main body of research on infrasound from Tolbachik Volcano and suggestions for future work on eruption dynamics using infrasound from other volcanoes. We use both regional and local infrasound data to track the dynamics of the 2012-2013 eruption of Tolbachik Volcano, Kamchatka, Russia. Analysis of regional data recorded at the IMS array IS44 in southern Kamchatka, ~384 km from the vent, focuses on the eruption onset in November 2012, while analysis of local data recorded 100-950 m from the vent focuses on activity in February and August 2013. Signals recorded from Tolbachik suggest an increase in eruptive intensity occurred from November 28-29, 2012. Local infrasound data are characterized primarily by repeated, transient explosion signals indicative of gas slug bursts. Three methods are employed to pick slug burst events in February and August, with all methods proving to be effective. The nature of slug bursts makes a monopole acoustic source model particularly fitting, permitting volume outux and slug radius calculations for individual events. Volume outuxes and slug radii distributions provide three possible explanations for the eruption style of Tolbachik Volcano from mid-February to late August. Cumulative outux for slug bursts (i.e. mass of emissions from individual bursts) derived by infrasound for both February and August range from <100 to 3000 kg. These values are greater than infrasound-derived emissions calculated at Pacaya Volcano, but less than those calculated at Mt. Erebus Volcano. From this, we determine slug bursts at Tolbachik Volcano in February and August were larger on average than those at Pacaya Volcano in 2010, but smaller on average than those at Mt. Erebus in 2008. Suggestions for future work are also given after analysis of acoustic waveforms from local infrasound data collected at Karymsky and Sakurajima Volcanoes. Activity at both of these volcanoes ranges from short-duration ash-rich explosions to longer-duration ash-rich explosions. A multiparameter dataset collected at Karymsky Volcano in August 2011 includes infrasound data, gas and ash data, and thermal imagery from eruptive events. Content of gas vs. ash, general plume characteristics, plume altitude above the vent, plume temperature, and SO₂ emission rates are correlated with acoustic waveform families identifed at each volcano using a cross correlation method. This preliminary analysis shows promise for correlating acoustic waveforms with eruptive activity and can likely be improved with future work.
    • Using self-organizing maps to detail synoptic connections between climate indices and Alaska weather

      Winnan, Reynir C.; Bhatt, Uma S.; Collins, Richard L.; Walsh, John E.; Wackerbauer, Renate A. (2015-12)
      Seasonal forecasts for Alaska strongly depend on the phases of Pacific Decadal Oscillation (PDO), El Niño-Southern Oscillation (ENSO), and warm water in the North Pacific called the North Pacific Mode or more popularly the "Pacific blob." The canonical descriptions of these climate indices are based on seasonal averages, and anomalies that are based on a long-term mean. The patterns highlight general geographical placement and display a sharp contrast between opposing phases, but this may be misleading since seasonal averages hide much of the synoptic variability. Self-organizing maps (SOMs) are a way of grouping daily sea level pressure (SLP) patterns, over many time realizations into a specified set of maps (e.g. 35 maps) that describe commonly occurring patterns. This study uses the SOMs in the context of climate indices to describe the range of synoptic patterns that are relevant for Alaska. This study found that the patterns common during a given phase of the PDO include subtle differences that would result in Alaska weather that is very different from what is expected from the canonical PDO description, thus providing some explanation for recent studies that find the PDO link to Alaska climate is weakening. SOMs analysis is consistent with recent studies suggesting that the pattern responsible for the 2014 Pacific warm blob is linked to tropical sea-surface temperature (SST) forcing. An analysis of the summer SLP SOMs in the context of Alaska wildland fires was also conducted. This analysis identified several commonly occurring patterns during summers with large areas burned. These patterns are characterized by low pressure in the Bering Sea, which would be consistent with increased storm activity and thus an ignition source for the fires. Identifying synoptic patterns that occur during a particular phase of a teleconnection index contributes towards understanding the mechanisms of how these indices influence the weather and climate of Alaska.
    • Using WRF/Chem, in-situ observations, and Calipso data to simulate smoke plume signatures on high-latitude pixels

      Madden, James Michael; Mölders, Nicole; Sassen, Kenneth; Prakash, Anupma; Grell, Georg (2014-05)
      The transport of wildfire aerosols provides concerns to people at or near downwind propagation. Concerns include the health effects of inhalation by inhabitants of surrounding communities and fire crews, the environmental effects of the wet and dry deposition of acids and particles, and the effects on the atmosphere through the scattering and absorption of solar radiation. Therefore, as the population density increases in Arctic and sub-Arctic areas, improving wildfire detection increasingly becomes necessary. Efforts to improve wildfire detection and forecasting would be helped if additional focus was directed toward the distortion of pixel geometry that occurs near the boundaries of a geostationary satellite's field of view. At higher latitudes, resolution becomes coarse due to the curvature of the Earth, and pixels toward the boundaries of the field of view become difficult to analyze. To assess whether it is possible to detect smoke plumes in pixels at the edge of a geostationary satellite's field of view, several analyses were performed. First, a realistic, fourdimensional dataset was created from Weather Research and Forecasting model coupled with Chemistry (WRF/Chem) output. WRF/Chem output was statistically compared to ground observations through the use of skill scores. Output was also qualitatively compared to vertical backscatter and depolarization products from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. After the quantitative and qualitative examinations deemed the model output to be realistic, synthetic pixels were constructed, appropriately sized, and used with the realistic dataset to examine the characteristic signatures of a wildfire plume. After establishing a threshold value, the synthetic pixels could distinguish between clean and smoke-polluted areas. Thus, specialized retrieval algorithms could be developed for smoke detection in strongly distorted pixels at the edge of a geostationary satellite's field of view.
    • Validating a GPS collar-based method to estimate parturition events and calving locations for two barren-ground caribou herds

      Hepler, Joelle D.; Griffith, Brad; Falke, Jeff; Roach, Jen (2019-12)
      In remote landscapes, it is difficult and expensive to document animal behaviors such as location and timing of parturition. When aerial surveys cannot be conducted as a result of weather, personnel or fiscal constraints, analyses of GPS collar movement data may provide an alternate way to estimate parturition rates and calving ground locations. I validated two methods (population-based method and individual-based method), developed to detect calving events of sedentary woodland caribou, on multiple years of data for two different migratory barren-ground caribou herds in Alaska, the Porcupine and Fortymile herds. I compared model estimates of population parturition rates, individual calving events, calving locations and calving dates to estimates from aerial survey data for both herds. For the Porcupine herd we also compared model estimates of annual calving ground sizes and locations of concentrated calving area centroids to those found with aerial survey. More years of data would be required for additional statistical power but for both the Porcupine and Fortymile herds, we found no significant difference between the population-based and individual-based method in: 1) individual classification rate accuracy (0.85 vs. 0.88, respectively; t = -7, P = 0.09, df = 1 and 0.85 vs. 0.83, respectively; t = 0.46, P = 0.69, df = 2) or 2) annual average distance from aerial survey calving locations (8.9 vs. 7.8 km, respectively; t = 0.16, P = 0.90, and 5.2 vs. 3.7 km, respectively; t = 1.03, P = 0.20). Median date of calving was estimated within 0-3 days of that estimated by aerial survey for both methods. Population parturition rate estimates from aerial survey, the population-based and individual-based methods were not significantly different for the PCH or FCH (0.91, 0.88 and 0.95, respectively; F = 0.67, P = 0.60, df = 2, and 0.83, 0.83 and 0.96, respectively; F = 3.85, P = 0.12, df = 2). Ultimately, more years of data would be required to support or reject the lack of significant differences between methods that we observed.
    • Variation of electron and ion density distribution along earth's magnetic field line deduced from whistler mode (wm) sounding of image/rpi satellite below altitude 5000 km

      Hazra, Susmita; Truffer, Martin; Simpson, William; Newman, David; Braddock, Joan (2015-05)
      This thesis provides a detailed survey and analysis of whistler mode (WM) echoes observed by IMAGE/RPI satellite during the years 2000-2005 below the altitude of 5000 km. Approximately 2500 WM echoes have been observed by IMAGE during this period. This includes mostly specularly reflected whistler mode (SRWM) echoes and ~400 magnetospherically reflected whistler mode (MRWM) echoes. Stanford 2D raytracing simulations and the diffusive equilibrium density model have been applied to 82 cases of MRWM echoes, observed during August-December of the year 2005 below 5000 km to determine electron and ion density measurements along Earth's magnetic field line. These are the first results of electron and ion density measurements from WM sounding covering L-shells ~1.6-4, a wide range of geomagnetic conditions (Kp 0+ to 7), and during solar minima (F10.2~70-120) in the altitude range 90 km to 4000 km. The electron and ion density profiles obtained from this analysis were compared with in situ measurements on IMAGE (passive recording; electron density (Ne)), DMSP (~850 km; Ne and ions), CHAMP (~350 km; Ne), Alouette (~500-2000 km; Ne and ions), ISIS-1, 2 (~600-3500 km; Ne, ions), AE (~130-2000 km; ions) satellites, bottom side sounding from nearby ionosonde stations (Ne), and those by GCPM (Global Core Plasma Model), IRI-2012 (International Reference Ionosphere). Based on this analysis it is found that: (1) Ne shows a decreasing trend from L-shell 1.6 to 4 on both the day and night sides of the plasmasphere up to altitude ~1000 km, which is also confirmed by the GCPM and IRI-2012 model. (2) Above ~2000 km altitude, GCPM underestimates Ne by ~30-90% relative to RPI passive measurements, WM sounding results. (3) Below 1500 km, the Ne is higher at day side than night side MLT (Magnetic Local Time). Above this altitude, significant MLT dependence of electron density is not seen. (4) Ion densities from WM sounding measurements are within 10-35% of those from the Alouette, AE, and DMSP satellites. (5) The effective ion mass in the day side is more than two times higher than night side below altitude ~500 km. (6) The O⁺/H⁺ and O⁺/(H⁺+H⁺+) transition heights at day side are ~300-500 km higher than night side; the transition heights from the IRI-2012 model lie within the uncertainty limit of WM sounding for night side, but for day side (L-shell>2.5) they are 200 km higher than WM uncertainty limits. (7) foF2 (F2 peak plasma densities) from ionosonde stations and the IRI-2012 model are ~1.5-3 MHz higher than those from WM sounding during daytime. These measurements are very important as the ion density profile along geomagnetic field lines is poorly known. They can lead to a better understanding of global cold plasma distribution inside the plasmasphere at low altitude and thereby bridge the gap between high topside ionosphere and plasmasphere measurements. These results will provide important guidance for the design of future space-borne sounders in terms of frequency and virtual range, in order to adequately cover ion density measurements at low altitudes and wide range of MLTs, solar and geophysical conditions.
    • Variational anodic oxidation of aluminum for the formation of conically profiled nanoporous alumina templates

      Wallace, Patrick D. (2012-05)
      Anodic oxidation of metals, otherwise known as anodization, is a process by which the metal in question is intentionally oxidized via an electrochemical reaction. The sample to be oxidized is connected to the anode, or positive side of a DC power source, while a sample of similar characteristics is attached to the cathode or negative side of the same power source. Both leads are then immersed in an acidic solution called the electrolyte and a current is passed between them. Certain metals such as aluminum or titanium anodized in this way form a porous oxide barrier, the characteristics of which are dependent on the anodization parameters including the type of acid employed as the electrolyte, pH of the electrolyte, applied voltage, temperature and current density. Under specific conditions the oxide formed can exhibit highly ordered cylindrical nanopores uniformly distributed in a hexagonal pattern. In this way anodization is employed as method for nanofabrication of ordered structures. The goal of this work is to investigate the effects of a varied potential difference on the anodization process. Specifically to affect a self-assembled conical pore profile by changing the applied voltage in time. Although conical pore profiles have been realized via post-processing techniques such as directed wet etching and multi-step anodization, these processes result in pore dimensions generally increasing by an order of magnitude or more. To date there has been reporting on galvanostatic or current variations which directly effected the resulting pore profiles, but to our knowledge there has not been a reported investigation of potentiostatic or voltage variation on the anodization process. We strive to realize a conical pore profile in process with the traditional two-step anodization method while maintaining the smallest pore dimensions possible. Pores having diameters below 20nm with aspect ratios about 1.0 would be ideal as those dimensions would be much closer to some of the characteristic lengths governing the quantum confined spatial domain. Thus we set out to answer the question of what effect a time varied potential difference will have on the traditional two-step anodization method, a technique we refer to as variational iodization, and if in fact conically profiled nanopores can be realized via such a technique.
    • Variations In Ice Flow And Glaciers Over Time And Space

      Elsberg, Daniel Harry; Harrison, William D. (2003)
      Ice flows and glaciers change over many time and spatial scales. Glacier surfaces evolve over decades, and this change affects the glacier-climate interaction. When a mass balance is computed using an outdated map, that computation does not reveal actual mass change. We present a method by which a mass balance computed with an outdated map can be transformed into actual mass change. While the actual volume change of a glacier is relevant to hydrological studies, the change that would have occurred on a static surface is more relevant to certain glacier dynamics problems and most climate problems. We term this the reference-surface balance and propose that such a balance is better correlated to climatic variations than the conventional one. Ice responds to stresses over time scales from seconds to millennia. We observed this using two independent strain-gauge systems to measure the strain rates as functions of depth and time at Siple Dome, Antarctica. One system employed optical fibers to measure annual strain rates over 175 m depth intervals. The other used one-meter resistance wires to measure strain approximately hourly at discrete depths. The long-term average strain rates from the two systems agreed to within 16%. The time-dependent strain rates measured beneath the divide by the resistance-wire gauges included intermittent strain events lasting up to 24 hours. We used the results from each system to compute an age-depth relationship assuming a time-independent ice flow geometry. Equilibrium line altitudes are related to climate, and they vary from year to year and among neighboring glaciers. We measured a regional pattern of equilibrium lines using remote sensing. Our goals were to evaluate the accuracy of such measurements, and to assess the spatial and temporal variability of the resulting data. Individual glacier equilibrium line altitudes varied by 100 m relative to a smoothed surface, and inter-annual variations in equilibrium line altitudes at one glacier were 74 m. A map of the regional pattern of equilibrium line altitudes shows variations of 1000 meters from the south to the north side of the range, but no major trend from east to west.
    • Vascular endothelial growth factor's angiogenic role in tumor growth and metastasis

      Kemp, Scott W.; Duffy, Lawrence K.; Clausen, Tom; Reynolds, Arleigh (2005-05)
      Angiogenesis and vasculogenesis are two very important processes in the development and maintenance of mammalian health. All structures of the body (human or animal) need certain essential elements in order to live thrive and maintain. The angiogenic role is to supply and support tissue with ample vasculature, thus providing a route of access for the transportation of essential nutrients and the removal of waste in a sustained fashion. Just like normal tissue, tumorogenic tissue is no exception; neoplastic tissue has the same nutritional requirements which must be supported via vascularization. Vascular endothelial growth factor (VEGF) has been shown to be a key mediating factor in the underlying cascade of chemical events leading to angiogenesis, which makes it a very important precursor molecule for early neoplasia detection. The overall purpose of this study was to establish circulatory baseline VEGF levels in healthy dog models. Baseline levels of VEGF in plasma will aid as a model in detection, comparison and evaluating of disease progression in sled dogs. There were significant differences between male and female dogs and exercising males and exercising females. A significant factor affecting baseline levels was gender. In addition there is some data which suggest that breed may playa role in baseline VEGF levels.
    • Vegetation reconstruction and climate evolution of Lake Dood, Darhad Basin, Northern Mongolia, over the past 4,500 years

      Wang, Yiming (2004-05)
      A semi-quantitative pollen index and stable isotopes of carbon and nitrogen are used to reconstruct late Holocene changes in moisture availability in the Darhad Basin, northern Mongolia. Palynomorphs extracted from cores of lake Dood indicate that the surrounding Darhad Basin was much wetter at 4,200 cal. yrs B.P. Beginning at 2,900 cal. yrs B.P., humidity in the Darhad Basin decreased until 300 cal. yrs B.P. Humidity and warmth returned briefly during the Medieval Warm Epoch, from 1,370 to 930 cal yrs B.P. (AD. 580 to 892). Increasing proportions of forest to steppe pollen types suggests a response to warmer summer temperatures and/or increased moisture during the 20th century warming. Differences in lake levels between lakes Dood, Telmen (300km to the south), and Hövsgöl (60km to the east), suggest that available moisture varies over short distances. Temperature changes driven by solar insolation appear to exert significant control over the regional water budgets of both lake Telmen and lake Hövsgöl, whereas moisture availability in the lake Dood region is affected by changes in atmospheric circulation over Eurasia.
    • Vegetation-Climate Interactions Along A Transition From Tundra To Boreal Forest In Alaska

      Thompson, Catharine Copass; McGuire, A. David (2005)
      The climate of the Alaskan Arctic is warming more rapidly than at any time in the last 400 years. Climate changes of the magnitude occurring in high latitudes have the potential to alter both the structure and function of arctic ecosystems. Structural responses reflect changes in community composition, which may also influence ecosystem function. Functional responses change the biogeochemical cycling of carbon and nutrients. We examined the structural and functional interactions between vegetation and climate across a gradient of vegetation types from arctic tundra to boreal forest. Canopy complexity combines vegetation structural properties such as biomass, cover, height, leaf area index (LAI) and stem area index (SAI). Canopy complexity determines the amount of the energy that will be available in an ecosystem and will also greatly influence the partitioning of that energy into different land surface processes such as heating the air, evaporating water and warming the ground. Across a gradient of sites in Western Alaska, we found that increasing canopy complexity was linked to increased sensible heating. Thus, vegetation structural changes could represent an important positive feedback to warming. Structural changes in ecosystems are linked to changes in ecosystem function. High latitude ecosystems play an important role in the earth's climate system because they contain nearly 40% of the world's reactive soil carbon. We examined Net Ecosystem Production (NEP) in major community types of Northern Alaska using a combination of field-based measurements and modeling. Modeled NEP decreased in both warmer and drier and warmer and wetter conditions. However, in colder and wetter conditions, NEP increased. The net effect for the region was a slight gain in ecosystem carbon; however, our research highlights the importance of climate variability in the carbon balance of the study region during the last two decades. The next step forward with this research will be to incorporate these results into coupled models of the land-atmosphere system. Improved representations of ecosystem structure and function will improve our ability to predict future responses of vegetation composition, carbon storage, and climate and will allow us to better examine the interactions between vegetation and the atmosphere in the context of a changing climate.
    • Vertex arboricity of triangle-free graphs

      Warren, Samantha; Gimbel, John; Faudree, Jill; Allman, Elizabeth (2016-05)
      The vertex arboricity of a graph is the minimum number of colors needed to color the vertices so that the subgraph induced by each color class is a forest. In other words, the vertex arboricity of a graph is the fewest number of colors required in order to color a graph such that every cycle has at least two colors. Although not standard, we will refer to vertex arboricity simply as arboricity. In this paper, we discuss properties of chromatic number and k-defective chromatic number and how those properties relate to the arboricity of trianglefree graphs. In particular, we find bounds on the minimum order of a graph having arboricity three. Equivalently, we consider the largest possible vertex arboricity of triangle-free graphs of fixed order.
    • Vitamin D, cognitive function, and oxidative stress: clues to overtraining syndrome?

      Jerome, Scott P.; Reynolds, Arleigh J.; Duffy, Lawrence K.; Sheppard, Dani K.; Watts, Phillip B. (2018-05)
      Overtraining syndrome (OTS) is characterized by an unexplainable drop in athletic performance. It affects primarily elite, endurance athletes, though sub-elite athletes are also affected. Although the deterioration in performance is often the most pronounced and troublesome symptoms for athletes, others range from severe fatigue and insomnia to depression and lack of mental concentration. There is no known diagnostic tool except for ruling out all other possible explanations for the abnormal performance. The only known remedy for OTS is rest. Some recover within months while others take a year or more. Some athletes never fully recovery and never return to pre-OTS performance levels. The exact mechanism behind OTS is unknown. Consensus has been reached among exercise science professionals that 1) an imbalance between stress load and recovery leads to OTS; 2) OTS exists on a spectrum of possible outcomes from different exercise/rest ratios; and 3) exercise is only one part of systemic stress that can lead to OTS. In addition to physical exercise, other factors such as environmental conditions, family dynamics, schoolwork, job stressors, and social pressures all contribute to the total stress load on the body. A severe and sustained imbalance between stress and rest is a likely contributor to OTS in athletes. I investigated biomarkers and psychological markers that, in concert, could be used to identify athletes who are at the greatest risk for developing OTS before the onset of symptoms. I examined vitamin D, cognitive function, and oxidative stress status in university cross country skiers in addition to athletic performance status during the competitive ski season. This study's results support three primary conclusions. First, collegiate endurance athletes are more prone to vitamin D insufficiency and deficiency than their sedentary counterparts. Second, collegiate cross country ski racers in the circumpolar North are unlikely to maintain adequate vitamin D during a competition season. Furthermore, vitamin D levels are likely to drop in the post-season, recovery period. Third, cognitive function is likely to be significantly higher in the post-season than during the competition season. Fourth, those who experienced a drop in performance during the competition season are more likely to show signs of oxidative stress. These findings may help to produce a screening tool for OTS.
    • Volcanic, tectonic, and tsunamigenic events recorded in peats near Millers Landing, Homer, Alaska

      Davis, Kathleen Melissa (2006-05)
      The Millers Landing peat deposit is located on the western side of Kachemak Bay, near Homer, Alaska. Distal tephra deposits from past eruptions of Augustine Volcano, Redoubt Volcano, Spurr Volcano, and Katmai Volcano are preserved within the peat. Evidence of active tectonism is found where a meter of marine silt overlies the peat deposits at Millers Landing. The marine mud deposits record co-seismic subsidence and post-seismic uplift as a result of a prehistoric great earthquake, ca. 1000 yr. B.P. along the northern Pacific plate boundary along the subduction interface. The uplift rate of Millers Landing over the past 1000 years has a minimum uplift rate of 3.0 mm/yr. Since 1995 Millers Landing has been an experiencing a post-seismic uplift rate of 5.4 +/- 0.6 mm/yr from the 1964 Prince William Sound earthquake. The Millers Landing peat deposits also contained nine layers of sand and beach gravel. The sedimentology is identical to classic tsunami depositional facies that have been identified in other tectonically active areas and we interpret these deposits as evidence of prehistoric tsunami events. The upper layer of two thick sand units, dated at ca. 3600 yr. B.P. by radiocarbon dating, is directly overlain by a 1.2 cm thick grayish white tephra. The tephra is from Redoubt Volcano and records a tsunami triggered by Mt. Redoubt's debris avalanche and lahar which are also dated at 3600 yrs B.P. The other sand deposits present within the peat are evidence of tectonically-triggered tsunamis. The recognition of tephras, tsunami deposits, and evidence of prehistoric co-seismic subsidence indicates the potential for geohazard assessment of Millers Landing and the entire Homer, Alaska region.
    • Volcanism On Unimak Island, Alaska, Usa: A Petrologic Focus On Shishaldin And Fisher Volcanoes

      Stelling, Peter L.; Eichelberger, John C. (2003)
      Volcanism on Unimak Island, Alaska represents a microcosm of Aleutian arc volcanism in general. This work focuses on two of the most significant features on Unimak Island, Fisher Caldera and Shishaldin Volcano. Despite frequent activity and potential for violent, hazardous eruptions, these volcanoes have been relatively unstudied. The present work details the processes occurring within Shishaldin and Fisher volcanoes, and highlights the complexities of their magma storage systems. Fisher Caldera began as a scattered series of independent stratocones formed from small, independent, non-communicating reservoirs. The 100 km 3 caldera-forming eruption (CFE) resulted from injection of three chemically distinct magmas, one being the largest magma batch to have passed through this system. Extensive fracturing during the CFE destroyed the pre-caldera infrastructure, and subsequent magmatism formed a single mixed reservoir. Post-caldera activity, stemming from this centralized chamber, produced several structurally controlled stratocones that erupted into the newly formed caldera lake. A tsunami generated by an explosive intra-caldera eruption catastrophically drained the caldera lake. Current activity is largely hydrothermal. The progression through which the Fisher system developed is similar to those seen in other caldera systems, yet has not been put forth in the literature as a common process. I suggest the Fisher sequence is an end-member in the spectrum of worldwide caldera formation, and present this process in a global context. Shishaldin Volcano has been formed through the concurrent activity of two separate magma systems, the products of each of which are compositionally distinct. Parental magmas for each series are both basalt, but have different trace-element signatures that require separate protoliths. Furthermore, distinct paths of subsequent chemical evolution are also required. One series shows evidence of ponding at high pressure prior to final ascent, whereas the magmas of the other series are directly emplaced in several small, shallow reservoirs. Results from both volcanoes tend to support a view involving complex magma storage: discrete magma batches with limited interaction rather than simple differentiation in a central chamber.* *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Adobe Acrobat; Microsoft Office.
    • Volcano Deformation And Subdaily Gps Products

      Grapenthin, Ronni; Freymueller, Jeffrey (2012)
      Volcanic unrest is often accompanied by hours to months of deformation of the ground that is measurable with high-precision GPS. Although GPS receivers are capable of near continuous operation, positions are generally estimated for daily intervals, which I use to infer characteristics of a volcano's plumbing system. However, GPS based volcano geodesy will not be useful in early warning scenarios unless positions are estimated at high rates and in real time. Visualization and analysis of dynamic and static deformation during the 2011 Tohokuoki earthquake in Japan motivates the application of high-rate GPS from a GPS seismology perspective. I give examples of dynamic seismic signals and their evolution to the final static offset in 30 s and 1 s intervals, which demonstrates the enhancement of subtle rupture dynamics through increased temporal resolution. This stresses the importance of processing data at recording intervals to minimize signal loss. Deformation during the 2009 eruption of Redoubt Volcano, Alaska, suggested net deflation by 0.05 km&sup3; in three distinct phases. Mid-crustal aseismic precursory inflation began in May 2008 and was detected by a single continuous GPS station about 28 km NE of Redoubt. Deflation during the explosive and effusive phases was sourced from a vertical ellipsoidal reservoir at about 7-11.5 km. From this I infer a model for the temporal evolution of a complex plumbing system of at least 2 sources during the eruption. Using subdaily GPS positioning solutions I demonstrate that plumes can be detected and localized by utilizing information on phase residuals. The GPS network at Bezymianny Volcano, Kamchatka, records network wide subsidence at rapid rates between 8 and 12 mm/yr from 2005-2010. I hypothesize this to be caused by continuous deflation of a ~30 km deep sill under Kluchevskoy Volcano. Interestingly, 1-2 explosive events per year cause little to no deformation at any site other than the summit site closest to the vent. I derive evidence for a very shallow source, likely within the edifice. This work shows that network design and individual plumbing system characteristics affect the ability to detect motion on subdaily and even weekly time scales, which stresses the importance of network scale considerations.
    • Volcano Seismicity in Alaska

      Buurman, Helena; West, Michael; Freymueller, Jeffrey; Prejean, Stephanie; Thompson, Glenn (2013-05)
      I examine the many facets of volcano seismicity in Alaska: from the short-lived eruption seismicity that is limited to only the few weeks during which a volcano is active, to the seismicity that occurs in the months following an eruption, and finally to the longterm volcano seismicity that occurs in the years in which volcanoes are dormant. I use the rich seismic dataset that was recorded during the 2009 eruption of Redoubt Volcano to examine eruptive volcano seismicity. I show that the progression of magma through the conduit system at Redoubt could be readily tracked by the seismicity. Many of my interpretations benefited greatly from the numerous other datasets collected during the eruption. Rarely was there volcanic activity that did not manifest itself in some way seismically, however, resulting in a remarkably complete chronology within the seismic record of the 2009 eruption. I also use the Redoubt seismic dataset to study post-eruptive seismicity. During the year following the eruption there were a number of unexplained bursts of shallow seismicity that did not culminate in eruptive activity despite closely mirroring seismic signals that had preceded explosions less than a year prior. I show that these episodes of shallow seismicity were in fact related to volcanic processes much deeper in the volcanic edifice by demonstrating that earthquakes that were related to magmatic activity during the eruption were also present during the renewed shallow unrest. These results show that magmatic processes can continue for many months after eruptions end, suggesting that volcanoes can stay active for much longer than previously thought. In the final chapter I characterize volcanic earthquakes on a much broader scale by analyzing a decade of continuous seismic data across 46 volcanoes in the Aleutian arc to search for regional-scale trends in volcano seismicity. I find that volcanic earthquakes below 20 km depth are much more common in the central region of the arc than they are in the eastern and western regions. I tie these observations to trends in magma geochemistry and regional tectonic features, and present two hypotheses to explain what could control volcanism in the Aleutian arc.
    • Volcano Seismology From Around The World: Case Studies From Mount Pinatubo (Philippines) Galeras (Colombia), Mount Wrangell And Mount Veniaminof (Alaska)

      Sanchez-Aguilar, John Jairo; McNutt, Stephen R.; Power, John A.; Freymueller, Jeffrey T.; Christensen, Douglas; Eichelberger, John (2005)
      A compilation of research papers in volcano seismology is presented: (1) to study the configuration of magma systems beneath volcanoes, (2) to describe unexpected effects of the shaking from a regional earthquake on volcanic systems, and (3) to integrate seismicity investigations into a conceptual model for the magma system of a volcano. This work was undertaken because much research in volcano seismology is needed to help in hazard assessment. The possible configuration of magma systems beneath Mount Pinatubo, Philippines, and Galeras Volcano, Colombia, is studied with b-value mapping. We suggest models for earthquake-volcanoes interactions by studying the declines in local seismicity at Mt. Wrangell and Mt. Veniaminof, Alaska, following the 3 November 2002 Denali Fault Earthquake (DFE). Finally, a model for the magmatic-hydrothermal system beneath Mt. Veniaminof is proposed by deriving a velocity model and relocating the earthquakes, and by studying the temporal changes of frequencies and attenuation (Q) at the source of long-period (LP) events. Results from b-value mapping confirm that volcanoes are characterized by localized zones of high b-values, and also indicate that the internal structure of volcanoes is variable. Analyses of the background seismicity at Mt. Veniaminof suggest that earthquakes result from locally-induced stresses and that LP events may represent the response of a shallow hydrothermal system to heat input from below. The study of declines in seismicity at Mt. Wrangell and Mt. Veniaminof volcanoes following the DFE indicates that the dynamic shaking from regional shocks can physically damage a volcano and together with the static stress changes can affect the local seismicity for extended periods. We conclude that the use of simple methods allows a better understanding of the seismicity at volcanoes in Alaska, but most importantly in developing countries where the small number of seismograph stations puts challenging limitations for research.
    • Volume Changes Of Alaska Glaciers: Contributions To Rising Sea Level And Links To Changing Climate

      Arendt, Anthony A.; Echelmeyer, Keith A. (2006)
      We have used airborne altimetry to measure surface elevations along the central flowline of 86 glaciers in Alaska, Yukon Territory and northwestern British Columbia (northwestern North America). Comparison of these elevations with contours on maps derived from 1950s to 1970s aerial photography yields elevation and volume changes over a 30 to 45 year period. Approximately one-third of glaciers have been re-profiled 3 to 5 years after the earlier profile, providing a measure of short-timescale elevation and volume changes for comparison with the earlier period. We have used these measurements to estimate the total contribution of glaciers in northwestern North America to rising sea level, and to quantify the magnitude of climate changes in these regions. We found that glaciers in northwestern North America have contributed to about 10% of the rate of global sea level rise during the last half-century and that the rate of mass loss has approximately doubled during the past decade. During this time, summer and winter air temperatures at low elevation climate stations increased by 0.2+/-0.1 and 0.4+/-0.2�C (decade)-1 respectively. There was also a weak trend of increasing precipitation and an overall lengthening of the summer melt season. We modeled regional changes in glacier mass balance with climate station data and were able to reproduce altimetry measurements to within reported errors. We conclude that summer temperature increases have been the main driver of the increased rates of glacier mass loss, but winter warming might also be affecting the glaciers through enhanced melt at low elevations and a change in precipitation from snow to rain, especially in maritime regions. Uncertainties in our calculations are large, owing to the inaccuracies of the maps used to provide baseline elevations, the sparsity of accurate climate data, and the complex and dynamic nature of glaciers in these regions. Tidewater, surging, and lake-terminating glaciers have dynamical cycles that are not linked in a simple way to climate variability. We found that regional volume losses can depend on one or several large and dynamic glaciers. These glaciers should be treated separately when extrapolating altimetry data to an entire region.
    • Vulture and other ornithological survey data in Annapurna and Manaslu Conservation regions

      Karmacharya, Dikpal Krishna; Gyawali, Seejan; Virani, Munir; Huettmann, Falk (2013-10-01)
      This dataset presents geo-referenced summaries of vulture and raptor sightings (from field work as well as from published sources 1977-2013), as well as general avian species lists and their detected abundances, for the Annapurna (ACA) and Manaslu Conservation Areas (MCA). In addition, compiled 'presence only' data of vultures are provided for Nepal and Northern India as well. The bounding box (decimal degrees) of the data coverage is 77.4966 til 87.0667 latitude and 26.3666 til 28.58333 longitude, and Altitude covers 100m til 7969m. The data consist of MS Excel and include 6 worksheets (all bird list, number of bird sighting and counting, descending number of individuals, vulture survey in ACA, raptors in Manaslu, and compiled presence only sightings of vultures for Nepal and Northern India). While this data set is reatively small, it includes a large and complex set of information for a vast and globally relevant region. The following raptor species are primarily covered in this data set: Upland Buzzard (Buteo hemilasius, TSN 175385), Himalayan Griffon (Gyps fulvus, 175487), Golden Eagler (Aquila chrysaetos, 175407), Himalayan Vulture (Gyps himalayensis,175488), Bearded Vulture (Gypaetus barbatus,175483), Egyptian Vulture (Neophron percnopterus, 175481) and White-Rumped Vulture (Gyps bengalensis, 175485). Smaller predators like Common Kestrel (Falco tinnunculus, 175620), Peregrine Falcon (Falco peregrinus,175604), Shikra (Accipiter badius, 55890), Bonelli's Eagle (Aquila fasciata, 175565), Black Kite (Milvus migrans,175469), Mountain Hawk Eagle (Spizaetus nipalensis, 175580), Spotted Owlet (Athene brama, 555472), Western Osprey (Pandion haliaetus, 175590) and Crested Serpent Eagle (Spilornis cheela, 175506) were also reported, In addition, overall app. 763 sighting locations of 143 species of birds are also featured in the data (english names as well as scientific names). Naturalists, bird watchers, modelers as well as investigators of raptors and other birds in the Nepal and Northern Indian regions will find great value in this data set.