• Implementing path coloring algorithms on planar graphs

      Bross, Daniel Aven; Chappell, Glenn; Lawlor, Orion; Hartman, Chris (2017-08)
      A path coloring of a graph partitions its vertex set into color classes such that each class induces a disjoint union of paths. In this project we implement several algorithms to compute path colorings of graphs embedded in the plane. We present two algorithms to path color plane graphs with 3 colors based on a proof by Poh in 1990. First we describe a naive algorithm that directly follows Poh's procedure, then we give a modified algorithm that runs in linear time. Independent results of Hartman and Skrekovski describe a procedure that takes a plane graph G and a list of 3 colors for each vertex, and computes a path coloring of G such that each vertex receives a color from its list. We present a linear time implementation based on Hartman and Skrekovski's proofs. A C++ implementation is provided for all three algorithms, utilizing the Boost Graph Library. Instructions are given on how to use the implementation to construct colorings for plane graphs represented by Boost data structures.
    • Implications for strain accommodation in an oblique subduction zone: new paleomagnetic and geologic data from the central Aleutian arc, Alaska

      Krutikov, Lena (2006-12)
      Oblique subduction results in partitioning of strain into arc-normal and arc-parallel components, and a complex pattern of upper plate deformation. Although partitioning of strain is observed in areas of oblique subduction around the world, the kinematics of strain accommodation are poorly understood. This is particularly true in the Aleutian arc because of a paucity of geologic and geophysical data. In the Aleutian arc, models previously proposed for forearc deformation have been characterized by clockwise rotation and westward translation of discrete tectonic blocks. This study utilizes two separate datasets to help constrain these mechanisms. The first step utilizes new high-resolution multibeam sonar data that provides a first detailed look at deformational structures on the seafloor. The second step is to examine the validity of paleomagnetic data previously collected from the arc, by re-measuring samples with improved methods. The multibeam sonar data reveal dense deformational patterns on the seafloor that suggest considerable diffuse strain between block boundaries. Remeasured paleomagnetic samples produce results that are similar to previous findings, but with reduced error bars and improved resolution. Younger rocks indicate little rotation, while samples from Amchtika Island indicate greater rotation than expected.
    • Implications of pore-scale distribution of frozen water for the production of hydrocarbon reservoirs located in permafrost

      Venepalli, Kiran Kumar (2011-08)
      Frozen reservoirs are unique with the extra element of ice residing in them along with the conventional components of a reservoir. The sub-zero temperatures of these reservoirs make them complicated to explore. This study investigates reduction in relative permeability to oil with decrease in temperature and proposes a best-production technique for reservoirs occurring in sub zero conditions. Core flood experiments were performed on two clean Berea sandstone cores under permafrost conditions to determine the sensitivity of the relative permeability to oil (kro) over a temperature range of 23°C to -10°C and for connate water salinities ranging from 0 to 6467 ppm. Both cores showed maximum reduction in relative permeability to oil when saturated with deionized water; they showed minimum reduction when saturated with 6467 ppm of saline water. Theoretically, the radius of ice formed in the center of the pore can be determined using the Kozeny-Carman Equation by assuming the pores and pore throats as a cube with 'N' identical parallel pipes embedded in it. With obtained values of kro as input to the Kozeny-Carman Equation at -10°C, the radius of ice dropped from 0.145 [upsilon]rn to 0.069 [upsilon]rn when flooding, water salinity is increased to 6467 ppm. This analysis quantifies the reductions in relative permeability solely due to different formation salinities. Other parameters like fluid saturations and pore structure effects also are discussed. Fluids like deionized water, saline water, and antifreeze (a mixture of 60% ethylene or propylene glycol with 40% water) were tested to find the best flooding agent for frozen reservoirs. At 0°C, 9% greater recovery was observed with antifreeze than with saline water. Antifreeze showed 48% recovery even at -10°C, at which temperature the rest of the fluids failed to increase production.
    • The Importance of communication in land use planning for interior Alaska: a participant observation study

      Lunsford, Olivia K.; Trainor, Sarah; Veazey, Pips; Dawe, Janice (2019-04)
      Three case studies (i.e., (1) FNSB Marijuana Zoning, (2) The Joint Land Use Study, and (3) Rethinking Smith Ranch) were examined in the context of land use planning to assist the reader in understanding some of the challenges a second-class borough in Alaska faces. The researcher utilized an opportunity with the Fairbanks North Star Borough to perform a participant observation study which demonstrated the complexity in engaging and communicating with citizens of the area. The researcher identified the three following critical themes and referenced planning literature to analyze them: (1) challenges to accomplishing goals, (2) the importance of communication, and (3) potential solutions to overcoming challenges. Upon identifying the challenges experienced both during the case studies, as well as outside of the case studies, the researcher determined possible solutions to help the borough’s Department of Community Planning overcome the difficulties associated with communication and engagement of citizens.
    • Improved Membrane Filtration For Water And Wastewater Using Air Sparging And Backflushing

      Psoch, Christian (2005)
      The goal of this research was to investigate methods and techniques that enhance mass transfer through the membranes. Two general types of fluids were investigated: synthetic wastewater treated in a membrane bioreactor (MBR) and natural and simulated river water. For both fluids, a wide range of solid concentrations (up to 18 g/L) were tested. The membranes investigated were all tubular modules at pilot scale between 0.75 and 1.20 m length, with tubular diameters of 5.5--6.3 mm, 0.2 mum pore size, and membrane surface areas of 0.036--0.1 m2. For flux enhancement, two techniques were applied: air sparging (AS), and backflushing (BF). Both techniques were compared with the sponge ball cleaning method. The experimental temperature ranged between 10 and 30�C, cross-flow velocities (CFV) ranged between 0.5 and 5.2 m/s, and transmembrane pressure (TMP) ranged between 30 and 350 kPa. Research results showed, that AS was able to enhance the conventional flux over weeks to months up to factor of 4.5 for river water and a factor of 3 for wastewater. At modest CFV of 1.5--2 m/s, AS was as successful as BF. If higher CFV (up to 5.2 m/s) were supplied for BF, this technique could enhance the wastewater flux by factor 4.5. The supply of AS and BF combined was superior to the single application even at moderate CFV. The major finding of this research was that cake thickness on the membrane surface was decreased by AS, contrary to research by other authors. AS can be used as substitute aeration in MBRs, without impairing the degradation performance. The combination of AS and BF generated the least filter cake, but the lowest fouling was observed for AS. An empirical equation was proposed to calculate the viscosity in a sidestream MBR depending on reactor temperature and mixed liquor suspended solids (MLSS).
    • An improved method of ice nucleus measurement

      Shih, Chi-Fan G. (1982-09)
      Ice nuclei, which initiate the ice nucleation process at a higher temperature than the homogeneous nucleation temperature, are essential for the initiation of the ice phase in clouds. Unfortunately, no standard method has been established for the measurement of ice nucleus concentration. The filter technique is a promising candidate if the tendency for ice nucleus concentrations to decreases as the volume sampled increases can be explained. For this study, an improved ventilation method for the development of exposed filters was developed and tested. The results were compared with results obtained in a static diffusion chamber. The volume effect was observed to be less with the new dynamic system. Further work needs to be done to find the optimum flow rate in order to reduce the vapor depletion problem to a minimum. The ratio of total counts of dynamic and static system appears to be a promising evaluation index.
    • Improved Modeling Of Turbulent Transport: From Noise In Transport Models To The Parareal Algorithm Applied To Full Turbulence Codes

      Samaddar, Debasmita; Newman, David (2010)
      Turbulence and turbulent transport are ubiquitous in nature and are of fundamental importance in everything from the spread of pollution to confinement in fusion plasmas. In order to study this, turbulence models need to be as realistic as possible and one must also be able to evolve the turbulence and the profiles of the quantities of interest on transport (long) time scales. Improving turbulence simulations by the introduction of new techniques forms the basis of this research. One part of this work involved improving the performance of a 1D transport model by the addition of noise. On a more fundamental level, studying long time dynamics for turbulence simulations is very difficult even with the fastest computers available now or in the near future. To help overcome this difficulty, a new way of simulating turbulence has been presented, namely parallelizing in time. Time parallelization of a fully developed turbulent system is a new application. Parallelizing the space domain to computationally solve partial differential equations has been extensively used and is one of the most common forms of parallelization. In contrast, the Parareal Algorithm parallelizes the time domain and has been found to significantly reduce the computational wall time in many simpler systems. Despite its success in other less complex problems, it has not yet been successfully applied to a turbulent system (to the best of our knowledge). If efficiently applied, this algorithm will allow study of the turbulent transport dynamics on transport time scales - something that has heretofore been very difficult. In this work, the results of applying the Parareal Algorithm to simulations of drift wave turbulence in slab geometry in which the relative dominance of the polarization and E x B nonlinearities are tuned artificially, are presented. These turbulent systems are in many ways similar to neutral fluid turbulence models, so success of the Parareal scheme in them expands the prospect of a broader range of application to many other turbulent problems. This thesis also presents the results of a modification to the algorithm. A model to study and predict the parameters governing the convergence of the scheme is also explored.
    • Improving CubeSat downlink capacity with active phased array antennas

      Klein, Jonathan; Hawkins, Joe; Thorsen, Denise; Raskovic, Dejan (2017-08)
      Power budgets on small satellites are restricted by the limited surface area for solar panels. This limits the power available for radio communications, which constrains the downlink budget. The limited transmit power translates to low downlink data rates on small satellites. Antenna gain from directive antennas may be a power efficient way of improving the downlink budget, thereby increasing the downlink rate of small satellites. This project focuses on the design and development of a prototype low-power, electrically-steered S-band phased array RF front-end suitable for a CubeSat that could efficiently increase the EIRP, permitting higher data rates. A prototype of the array has been constructed and tested in an anechoic chamber. The four element array provides a minimum gain of 2.5 dB and average gain of 5 dB compared to a single patch antenna element with a 5W power envelope across a range of up to 60 degrees from broadside of the array.
    • Improving postsecondary transitions for students in rural Alaska: applying solution focused brief therapy in the school setting

      Elliott, Jill M.; Cook, Christine; Gifford, Valerie; Simpson, Joni (2015)
      Successful postsecondary transitions present several challenges for adolescents, and statistics show that Alaska Native youth experience additional adverse conditions and risks compared to their peers in the dominant culture. An effective intervention plan may assist rural Alaskan students in obtaining desirable education and increase opportunities for achieving personal and professional goals. This project is focused on answering the following research questions: What research has been done to show that SFBT groups could be effective in rural school settings to aid in postsecondary transitions? What components are necessary to include in an effective transition support plan for rural Alaskan students? A literature review was conducted to gain insight as to the aspects of Alaska Native culture that influence counseling outcomes, information regarding current postsecondary transition programs that are available, and the key facets of career development interventions for adolescents. This research guided the creation of a small group counseling curriculum that is grounded in the tenets of Solution Focused Brief Therapy and Family Systems Theory. The activities and discussion that are incorporated into the project target high schools in rural Alaska, and are designed to increase awareness, enhance self-efficacy, and embrace family, community and culture as vital supports in the career development process of adolescents.
    • Improving the renovation, repair and painting training course to eliminate childhood lead poisonings: Wisconsin observations

      Hildebrandt, Anke M.; McBeath, Gerald; Meek, Chanda; Greenberg, Joshua (2013-12)
      In 2011, I worked briefly with the Asbestos and Lead Program for the State of Wisconsin. It was my job to conduct audits of our training providers as well as on-site inspections of work sites. During my time there I discovered a real disconnect between what I saw in the field and what is taught in class. Wisconsin has its own lead rules that are more stringent than the EPA's. After taking a critical look at the EPA's Renovation, Repair and Painting Rule (RRP) curriculum, I saw where the problems lay. The required hands-on training does not present the skills in a logical order and the demonstration is not similar enough to reality to be retained and transferred to a worksite consistently. Instead of contractors and homeowners learning how to conduct a job safely from start to finish, they are presented specific skills broken down into 11 skill sets. Over a four month time span I took the EPA curriculum and wrote scripts, videotaped, edited and narrated training videos with the assistance of Department of Health Service staff to eliminate the disconnect between the classroom learning and the real world. The videos demonstrate lead-safe work practices in a manner intended to increase retention rates. The videos were released in July 2012, and since then inspection statistics show a 13 percent decrease in offenses from certified workers and a 31 percent decrease in violations overall. Data for the first half of 2013 also indicated a positive trend; violations by certified contracts are down an additional percent. The Alaska Department of Environmental Conservation conducted a study in 1996, finding that 62 percent of Alaska private homes were built prior to 1979. This means approximately 49 percent of all Alaskan homes contain lead-based paint, 14 percent higher than the national average. The use of lead-based paint in colder regions is not uncommon. Lead-based paint was praised for its durability and longevity, making it ideal for regions in the circumpolar north. Americans spend nearly 90 percent of their time indoors. In cold climates, such as the Arctic, people tend to spend even more time indoors (EPA, 2012). Increased time indoors allows for increased wear on friction surfaces in the home. For children, deteriorating lead-based paint and lead in house dust are the primary and often most concentrated sources of lead (CDC, 2012). The Center for Disease Control reports that in 2004 there were 143,000 deaths and a loss of 8,977,000 disability-adjusted life years attributed to lead exposure worldwide. The primary cause was lead-associated adult cardiovascular disease and mild intellectual disability in children. Children represent approximately 80 percent of the disease impact attributed to lead, with an estimated 600,000 new cases of childhood intellectual disabilities resulting from blood lead levels (BLLs) greater than 10 υg/dL(CDC, 2012).
    • Improving ultimate recovery in the Granite Point field Tyonek C sands

      Nenahlo, Thomas L.; Dandekar, Abhijit; Patil, Shirish; Ning, Samson (2018-12)
      The objective of this research is to determine how the ultimate recovery of the Granite Point field can be improved. An understanding of the depositional setting, structure, stratigraphy, reservoir rock properties, reservoir fluids, aquifer, and development history of the Granite Point field was compiled. This was then leveraged to provide recommendations on how the ultimate recovery can be improved. The Granite Point field Tyonek C sands are located on an anticline structure at 8,000' to 11,000' SSTVD within the offshore Cook Inlet basin. These sands were deposited in a fluvial environment with the source material provided by the Alaska Range to the northwest. Due to uplifting, the Tyonek C sands are of relatively low porosity for their depth. The sands thin, become more numerous, and are of generally lower porosity from southwest to northeast. Oil quality is excellent and displacement efficiency of the reservoir rock with water flood exceeds 50% at breakthrough. Although displacement efficiency is high, the relative permeability to water is extremely low. The fracture gradient of the reservoir rock is on the order of magnitude of 1.0 psi/ft. Many initiatives were undertaken throughout the history of the Granite Point field to improve the rate and resource recovery, all of which were met with negligible success with the exception being the introduction of horizontal wells that were first drilled in the early 1990's. The underlying reason for the lack of success of these other initiatives is the low effective permeability to oil and the extremely low effective permeability to water. Secondary recovery with water injection was successful in the early stage of development, and can be in the future, but only when applied between wells that are connected by a sand of acceptable porosity. The results of this research indicate that to improve the ultimate recovery of the Granite Point field a thorough quantification of aquifer and injection water movement must first be understood, then horizontal wells can be placed in appropriate locations to improve the offtake and leverage the weak aquifer drive to provide pressure support.
    • In quest of authentic Yup'ik art: concepts of tradition

      Simon, Katrin A. (2007-08)
      My interest is in the various perceptions - including my own - that people have of the concepts 'traditional' and 'authentic' as it applies to contemporary Alaska Native art and artists. With my research, I aim to examine Yup'ik art from different perspectives and to investigate the different cultural standards and definitions that exist about what constitutes 'authentic' Yup'ik art and artists. Consumers, collectors, the government, and Yup'ik artists from diverse cultural backgrounds all have different concepts of what authentic, traditional Yup'ik art constitutes. I believe it is important to investigate Native art, as much as possible, without reservations and prejudgements as to their concepts of art and to listen closely to the artists' voice, especially when it contradicts our own perceptions.
    • An in vitro analysis of neuronal survival in response to hormones and photoperiod in the HVc of the songbird Junco hyemalis

      Humphries, Catherine Martin (2003-12)
      The ability of songbirds to sing is essential for their survival, proper reproductive behavior, and territorial establishment. Male and female juvenile passerine songbirds learn their song through the formation of a song template in their earliest days of life, first by listening to their parents, and then followed by auditory feedback against their own templates to crystallize their individual songs. However, in most passerine species, only the adult males actually sing on a seasonal basis with little to no singing during winter, followed by a phase of song production in the spring in correlation with increased plasma testosterone concentration and extended photoperiods. While the production of new neurons in the song system of adult males is continuous throughout the year, a counterbalancing turnover of these neurons must exist until the spring, when a three- to four-fold decrease in dying HVc (hyperstriatum pars ventralis caudale or higher vocal center) neurons in males initiates song production. We hypothesized that testosterone, under the influence of increased photoperiod, attenuates the rate of programmed cell death (apoptosis) of newly generated neurons migrating into the HVc song nucleus in the wild arctic songbird Junco hyemalis. Using an organotypic culture system, we examined the effect of testosterone and [beta]-estradiol on the degree of apoptosis in the HVc obtained from photo stimulated and non-photo stimulated male and female juncos. We employed a TUNEL assay and BrdU-labeling to detect and quantify apoptosis. We found that hormonal treatment with testosterone, and [beta]-estradiol in photostimulated birds only, extends the lifespan of cells within the HVc compared to controls, as shown by BrdU labeling, and decreasing apoptosis, as shown by TUNEL assay.
    • In whatever wreckage remains

      Kirk, Maeve; Brightwell, Geraldine; Coffman, Christine; Farmer, Daryl (2016-05)
      In Whatever Wreckage Remains is a collection of realistically styled short stories that examines both the danger and potential of change. These pieces are driven by the psychology of the men and woman roaming these pages, seeking to provide insight into the unique weight of their personal wreckage. From a woman craving motherhood who combs through forests searching for the unclaimed body of a runaway to a spitfire retiree’s struggle to accept her husband’s failing health, the individuals in these narratives are all navigating transitional spaces in their lives, often unwillingly. Along the way, they must balance the pressures of familial roles, romantic relationships, and personal histories while attempting to reshape their understanding of self. These stories explore the shifting landscape of identity, belonging, and the sometimes conflicting responsibilities we hold to others and to ourselves.
    • In-cylinder pressure based combustion performance evaluation of syntroleum synthetic and conventional diesel fuels

      Kandulapati, Praveen K. (2006-12)
      Synthetic fuels produced from non-petroleum based feedstocks can effectively replace the depleting, petroleum-based conventional fuels while significantly reducing emissions. The zero sulfur content and the near zero percentage of aromatics in the synthetic fuels make them promising clean fuels to meet the upcoming emissions regulations. However, due to their significantly different properties when compared to conventional fuels, existing engines must be tested extensively to study their performance with the new fuels. The current work presents a detailed in-cylinder pressure measurement based comparison of the combustion performance of a natural gas derived synthetic diesel fuel, supplied by Syntroleum Corporation based in Tulsa, OK, and No.1 conventional diesel fuel. These fuels were tested on a Detroit Diesel Series 50 engine with an advanced electronically controlled fuel injection system. The differences observed in various combustion related parameters and their possible effects on engine performance and emissions are documented. The adaptability of the existing ECM to optimize engine performance with the new fuel was also studied.
    • An in-season management system for sockeye salmon returns to Lynn Canal, southeast Alaska

      McPherson, Scott A. (1990-09)
      An in-season management system was developed for four stocks of sockeye salmon (Oncorhynchus nerka) from Chilkoot and Chilkat Lakes in Southeast Alaska, using a total run (catch + escapement) database built from analysis of 132,000 scale samples. Separate management objectives were defined for early and late stocks from each lake. A Ricker model, with nonlinear least squares and a bootstrap procedure, was used to estimate optimal escapement levels, which were lower than previous estimates, and precision bounds. Comparison of several in-season forecasting models based on run timing showed that a model combining a preseason forecast with average proportion forecasts was most accurate. Average proportion forecasts were improved by timing shifts identified by inflection points. Linear regression was used to forecast Chilkat Lake escapement in-season. Accuracy of the best forecasting models for each analysis was ≤ 25% by the first quartile of abundance.
    • In-Situ monitoring of sea ice dielectric properties and implications for the tracking of seasonal evolution of microstructure

      O'Sadnick, Megan; Eicken, Hajo; Truffer, Martin; Pettit, Erin (2015-08)
      The microstructure of sea ice evolves throughout the seasonal cycle, from ice formation in the fall through melt in the summer. Observations of this seasonal evolution and its effect on the interaction between sea ice and the surrounding environment face fundamental challenges, however. Any removal of ice cores to obtain data on ice properties results in the loss of brine and alterations of microstructure. The remoteness of field sites also limits observations. Methods to monitor sea ice microstructure continuously and non-destructively are therefore being explored. This thesis examines the potential for the electric properties of sea ice, highly sensitive to the brine distribution within the ice, to serve as a proxy for microstructure and hence other ice transport properties. Throughout the Spring of 2013 and 2014, measurements of low frequency complex dielectric permittivity in the range of 10 Hz to 95 kHz were made in landfast ice off the coast of Barrow, Alaska. Temperature and salinity measurements and ice samples were collected for ice microstructure characterization. Results reveal a significant correlation between measurements of complex dielectric permittivity, brine volume fraction, and microstructural characteristics including pore volume and connectivity. The influence of temperature and salinity variations and further explanation of the relationships between ice properties, microstructural characteristics, and dielectric behavior are explored through multivariate analysis of the combined data set. The findings are discussed in terms of future research directions and promising approaches for in-situ ice property monitoring based on dielectric measurements.
    • Inconstant Endeavors: The Elusiveness Of The Anti-Heroine

      Williamson, Lianne; Bird, Roy K.; Burleson, Derick; Coffman, Christine; Weiss, David; Vettel-Becker, Patricia (2009)
      The anti-heroine is a difficult woman to define. The intent of this project was to find the markers and signifiers for the character of the anti-heroine. Only recently, with modernism and then post-modernism, has the equation of beauty = woman started to change. What has occurred is the opposite, the grotesque. How are female artists using the grotesque to open up the possibilities for how women are allowed to act? Although women are now being allowed, in film, to DO what men do, i.e. kill people, they are still coming across in stereotypically female ways. The women are still beautiful, they use violence, they have to be more manly than men. How has second and third wave feminist theory opened up the realm of writing about the bitch? In the past decade literally thousands of books have been written with "bitch" in the title. Is the "bitch" the same thing as the anti-heroine? In the creative part of the dissertation, I have attempted to write a multi-faceted anti-heroine who isn't necessarily a bitch, doesn't participate in violence, has a sense of humor, and is writing about both female and feminist subjects. The critical essay looks at literary influences on my writing and my own definition of the anti-heroine. My research has shown that the anti-heroine is an extremely elusive character and is quite different from the male anti-hero. What we can say is that she defies stereotyping, is a complex creation, may or may not be beautiful, and acts rather than reacts.
    • Incorporating funds of knowledge in school gardens

      Hill, Danitza; Hogan, Maureen; Topkok, Sean; Henry-Stone, Laura (2017-12)
      Incorporating "funds of knowledge" with schoolyard gardening enriches a child's experience by interacting with their families, local community organizations, school faculty, and other children. A garden community is a social setting and the relationships established by working together cultivate a long-lasting commitment to education. Children are excited to learn, willing to participate, and take ownership of acquiring life skills that are fundamental to pass on from generation to generation. Incorporating "funds of knowledge" provides a venue for those inherited skill sets to be incorporated into the mainstream curriculum of the classroom. The small, yet emblematic, group of children that participated in this project at Leupp Public School were able to gain an appreciation for planting and growing a garden by being Youth Participant Action Researchers. Conducting home visits to some of the family homes also brought an invitation for increased participation in the school garden. The children incorporated their culture of gardening by learning from elders, community gardeners and their families.
    • Increases And Fluctuations In Thermal Activity At Mount Wrangell, Alaska (Volcano, Glacier)

      Motyka, Roman John (1983)
      The objectives of this study were to document and interpret changes in thermal activity at two of three craters located on the rim of the ice-filled summit caldera of Mount Wrangell, an active glacier-clad shield volcano in south-central Alaska. The technique of "glacier calorimetry" was developed, through which changes in the volume of glacier ice in the craters and caldera were measured and related to changes in heat flow. Chemical analyses of gases and acid-thermal waters provided information on the underlying heat source. In 1965, thermal activity began increasing at both the North and West Craters. During the ensuing years, heat flow increased significantly at the North Crater, although in a highly fluctuating manner, while gradually declining at the West Crater. Pulses in heat flow at the North Crater occurred in 1966-68 and 1972-74, with both pulses followed by a four-year decline in activity. Increases in heat flow began again in 1978-79 and have continued unabated through the summer of 1983. Over 80 percent of the 4.4 x 10('7)m('3) ice volume within the crater in 1966 was melted by 1982, and the meltwaters have drained or evaporated from the crater. The subsequent rapid development of numerous fumaroles, the large dry-gas proportion of SO(,2) (27 percent), and the inferred presence of gaseous HCl indicate that a shallow degassing magma body is the source of heat driving the thermal system. Seismically induced fracturing above the magma body is hypothesized to explain the initial increases in thermal activity. The resulting massive influx of meltwaters into the subsurface is suggested as the cause of the fluctuations in heat flow. The continued increase in activity since 1979 suggests that the volume of meltwater being generated is no longer sufficient to quench the heat source beneath the crater.