Permafrost Monthly Alerts (PMAs)

16005204 Jiang Nan (Chinese Academy of Sciences, State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Shenyang, China); Li Yang; Zheng Chenggang; Chen Lijun; Wei Kai; Feng Jiao and Tian Jihui. Characteristic microbial communities in the continuous permafrost beside the bitumen in Qinghai-Tibetan Plateau: Environmental Earth Sciences, 74(2), p. 1343-1352, illus. incl. 3 tables, 55 ref., July 2015.

Although research on microorganisms in the global ecosystem has considerably increased, there is still incomplete understanding of the microbial communities in alpine permafrost due to the inaccessibility. In this study, the microbial composition and diversity in the continuous permafrost beside the bitumen in the Qiangtang basin (CPBQ) was investigated by 454 pyrosequencing. Among the bacterial communities, the phylum Actinobacteria was dominant, ranging from 33.42 to 48.04 %, followed by Proteobacteria and Acidobacteria. In addition to the three characteristic phyla, Planctomycetes, Chloroflexi, and Nitrospirae were also important in the CPBQ. Crenarchaeota, especially the ammonia-oxidizing archaea Soil Crenarchaeotic Group (SCG), was the main archaea in the CPBQ. Moreover, four fungal phyla, Ascomycota, Mucoromycotina, Chytridiomycota and Glomeromycota, were detected in the CPBQ. Mortierella, Fusarium, and Tetracladium were the main genera. On the average, the proportion of No_rank and unclassified sequences in bacteria and fungi were high at low taxonomic levels, which could extend the list of extreme environmental microbial candidate divisions. The demonstrations of the microbial communities in the CPBQ could provide key data to improve the knowledge of microbes in the terrestrial extreme environments. Copyright 2015 Springer-Verlag Berlin Heidelberg

DOI: 10.1007/s12665-015-4124-1

16006855 Oliva, Marc (University of Lisbon, Institute of Geography and Spatial Planning, Centre for Geographical Studies, Lisbon, Portugal) and Ruiz-Fernández, Jesús. Coupling patterns between para-glacial and permafrost degradation responses in Antarctica: Earth Surface Processes and Landforms, 40(9), p. 1227-1238, illus. incl. 3 tables, geol. sketch maps, 64 ref., July 2015.

The recently deglaciated environments in maritime permafrost regions are usually affected by very active paraglacial processes. Elephant Point is an ice-free area of 1.16 km2 located in the SW of Livingston island (South Shetland Islands, Antarctica). Between 1956-2010 the retreat of the ice cap covering most part of this island has exposed 17.3% of the land surface in this peninsula. Two geomorphological units were identified in this new ice-free area: a moraine extending from the western to the eastern coastlines and a relatively flat proglacial surface. The glacier in 1956 sat in contact with the northern slope of the moraine, but its accelerated retreat--in parallel to the warming trend recorded in the Antarctic Peninsula--left these areas free of glacier ice. Subsequently, the postglacial evolution was controlled by the relaxation phase typical of paraglacial systems. The typology and intensity of geomorphological processes show a significantly different dynamics between the southern and northern slopes of the moraine. This pattern is related to the different stage of paraglacial adjustment in both slopes. In the southern side, on coarser sediments, pronival ramparts, debris flows and alluvial fans are distributed, with a low to moderate activity of slope processes. In the northern side, mass wasting processes are extremely active on fine-grained unconsolidated sediments. Ice-rich permafrost is being degraded by thermokarst processes. Landslides and mudflows transfer large amounts of sediments down-slope. The surface affected by retrogressive-thaw slumps in the moraine has been quantified in 24,172 m2, which accounts for 9.6% of its surface. The abundance of kettle-lakes is also indicative of the degradation of the ground ice. Paraglacial processes are expected to continue in the moraine and proglacial area in the near future, although their intensity and duration will depend on the magnitude and rate of future climate trends in the northern Antarctic Peninsula. Copyright Copyright 2015 John Wiley & Sons, Ltd.

DOI: 10.1002/esp.3716

16000963 Hodgkins, Suzanne B. (Florida State University, Department of Earth, Ocean, and Atmospheric Science, Tallahassee, FL); Tfaily, Malak M.; McCalley, Carmody K.; Logan, Tyler A.; Crill, Patrick M.; Saleska, Scott R.; Rich, Virginia I. and Chanton, Jeffrey P. Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production: Proceedings of the National Academy of Sciences of the United States of America, 111(16), p. 5819-5824, illus. incl. 2 tables, 63 ref., April 22, 2014.

Carbon release due to permafrost thaw represents a potentially major positive climate change feedback. The magnitude of carbon loss and the proportion lost as methane (CH₄) vs. carbon dioxide (CO₂) depend on factors including temperature, mobilization of previously frozen carbon, hydrology, and changes in organic matter chemistry associated with environmental responses to thaw. While the first three of these effects are relatively well understood, the effect of organic matter chemistry remains largely unstudied. To address this gap, we examined the biogeochemistry of peat and dissolved organic matter (DOM) along a ~40-y permafrost thaw progression from recently- to fully thawed sites in Stordalen Mire (68.35°N, 19.05°E), a thawing peat plateau in northern Sweden. Thaw-induced subsidence and the resulting inundation along this progression led to succession in vegetation types accompanied by an evolution in organic matter chemistry. Peat C/N ratios decreased whereas humification rates increased, and DOM shifted toward lower molecular weight compounds with lower aromaticity, lower organic oxygen content, and more abundant microbially produced compounds. Corresponding changes in decomposition along this gradient included increasing CH₄ and CO₂ production potentials, higher relative CH₄/CO₂ ratios, and a shift in CH₄ production pathway from CO₂ reduction to acetate cleavage. These results imply that subsidence and thermokarst-associated increases in organic matter lability cause shifts in biogeochemical processes toward faster decomposition with an increasing proportion of carbon released as CH₄. This impact of permafrost thaw on organic matter chemistry could intensify the predicted climate feedbacks of increasing temperatures, permafrost carbon mobilization, and hydrologic changes.

DOI: 10.1073/pnas.1314641111

16005973 Shirokova, L. S. (Russian Academy of Science, Institute of Ecological Problems of the North, Arkhangelsk, Russian Federation); Pokrovsky, Oleg S.; Kirpotin, S. N.; Desmukh, C.; Pokrovsky, B. G.; Audry, S. and Viers, J. Biogeochemistry of organic carbon, CO₂, CH₄, and trace elements in thermokarst water bodies in discontinuous permafrost zones of Western Siberia: in Marine ecosystem connections; essential indicators of healthy, productive and biologically diverse seas (Painting, Suzanne J., editor; et al.), Biogeochemistry (Dordrecht), 113(1-3), p. 573-593, illus. incl. 2 tables, sketch map, 95 ref., May 2013.

Active processes of permafrost thaw in Western Siberia increase the number of soil subsidencies, thermokarst lakes and thaw ponds. In continuous permafrost zones, this process promotes soil carbon mobilisation to water reservoirs, as well as organic matter (OM) biodegradation, which produces a permanent flux of carbon dioxide (CO₂) to the atmosphere. At the same time, the biogeochemical evolution of aquatic ecosystems situated in the transition zone between continuous permafrost and permafrost-free terrain remains poorly known. In order to better understand the biogeochemical processes that occur in thaw ponds and lakes located in discontinuous permafrost zones, we studied »30 small (1-100,000 m²) shallow (<1 m depth) lakes and ponds formed as a result of permafrost subsidence and thaw of the palsa bog located in the transition zone between the tundra and forest-tundra (central part of Western Siberia). There is a significant increase in dissolved CO₂ and methane (CH₄) concentration with decreasing water body surface area, with the largest supersaturation with respect to atmospheric CO₂ and CH₄ in small (<100 m²) permafrost depressions filled with thaw water. Dissolved organic carbon (DOC), conductivity, and metal concentrations also progressively increase from large lakes to thaw ponds and depressions. As such, small water bodies with surface areas of 1-100 m² that are not accounted for in the existing lake and pond databases may significantly contribute to CO₂ and CH₄ fluxes to the atmosphere, as well as to the stocks of dissolved trace elements and organic carbon. In situ lake water incubation experiments yielded negligible primary productivity but significant oxygen consumption linked to the mineralisation rate of dissolved OM by heterotrophic bacterioplankton, which produce a net CO₂ flux to the atmosphere of 5 ± 2.5 mol C m² year^-1. The most significant result of this study, which has long-term consequences on our prediction of aquatic ecosystem development in the course of permafrost degradation is CO₂, CH₄, and DOC concentrations increase with decreasing lake age and size. As a consequence, upon future permafrost thaw, the increase in the number of small water bodies, accompanied by the drainage of large thermokarst lakes to the hydrological network, will likely favour (i) the increase of DOC and colloidal metal stocks in surface aquatic systems, and (ii) the enhancement of CO₂ and CH₄ fluxes from the water surface to the atmosphere. According to a conservative estimation that considers that the total area occupied by water bodies in Western Siberia will not change, this increase in stocks and fluxes could be as high as a factor of ten. Copyright 2013 Springer Science+Business Media Dordrecht and 2012 Springer Science+Business Media B.V.

DOI: 10.1007/s10533-012-9790-4

16006086 Ekici, A. (Max Planck Institute for Biogeochemistry, Department of Biogeochemical Integration, Jena, Germany); Beer, C.; Hagemann, S.; Boike, J.; Langer, M. and Hauck, C. Simulating high-latitude permafrost regions by the JSBACH terrestrial ecosystem model: Geoscientific Model Development (GMD), 7(2), p. 631-647, illus. incl. 1 table, sketch map, 105 ref., 2014.

The current version of JSBACH incorporates phenomena specific to high latitudes: freeze/thaw processes, coupling thermal and hydrological processes in a layered soil scheme, defining a multilayer snow representation and an insulating moss cover. Evaluations using comprehensive Arctic data sets show comparable results at the site, basin, continental and circumarctic scales. Such comparisons highlight the need to include processes relevant to high-latitude systems in order to capture the dynamics, and therefore realistically predict the evolution of this climatically critical biome.

DOI: 10.5194/gmd-7-631-2014

16006852 Bardou, Eric (Centre de Recherche sur l'Environnement Alpin, Sion, Switzerland); Favre-Bulle, Guillaume; Faucheux, Claire; Jeannée, Nicolas and Ornstein, Pascal. Process oriented use of geostatistics to analyse creeping para-glacial features: Earth Surface Processes and Landforms, 40(9), p. 1191-1201, illus. incl. geol. sketch map, 49 ref., July 2015.

Complex para-glacial systems may show signs of destabilization leading to frequent and potentially hazardous debris-flows. Understanding creeping permafrost displacement over a period of time is therefore crucial for hazard management and risks assessment. This paper presents our methodology for estimating creeping permafrost displacement based upon data derived from various survey methods and demonstrates its relevance on the Glacier Bonnard system in southern Switzerland. Geostatistical processing allowed estimation of the displacement intensity over the area of interest, as well as assessment of the interpolation quality. Although the local measurement network needs to be refined, the results largely improve the understanding of the Bonnard para-glacial system, though highlighting the need to locally refine the measurement network. In the present case, the destabilized front advances at ~1 m/a and the upstream creeping part at ~0.4 m/a. Variance analysis also provide objective thresholds that could be used to distinguish underlying physical processes. Copyright Copyright 2015 John Wiley & Sons, Ltd.

DOI: 10.1002/esp.3711

16006828 Mellon, Michael T. (Southwest Research Institute, Department of Space Studies, Boulder, CO); McKay, Christopher P. and Heldmann, Jennifer L. Polygonal ground in the McMurdo dry valleys of Antarctica and its relationship to ice-table depth and the recent Antarctic climate history: Antarctic Science, 26(4), p. 413-426, illus. incl. 1 table, 44 ref., August 2014.

The occurrence of dry permafrost overlying ice-rich permafrost is unique to the Antarctic Dry Valleys on Earth and to the high latitudes of Mars. The stability and distribution of this ice are poorly understood and fundamental to understanding the Antarctic climate as far back as a few million years. Polygonal patterned ground is nearly ubiquitous in these regions and is integrally linked to the history of the icy permafrost and climate. We examined the morphology of polygonal ground in Beacon Valley and the Beacon Heights region of the Antarctic Dry Valleys, and show that polygon size is correlated with ice-table depth (the boundary between dry and ice-rich permafrost). A numerical model of seasonal stress in permafrost shows that the ice-table depth is a dominant factor. Remote sensing and field observations of polygon size are therefore important tools for investigating subsurface ice. Polygons are long-lived landforms and observed characteristics indicate no major fluctuations in the ice-table depth during their development. We conclude that the Beacon Valley and Beacon Heights polygons have developed for at least 10⁴ years to achieve their present mature-stage morphology and that the ice-table depth has been stable for a similar length of time.

DOI: 10.1017/S0954102013000710

16006250 Philben, Michael (University of South Carolina, Department of Biological Sciences and Marine Science Program, Columbia, SC); Kaiser, Karl and Benner, Ronald. Biochemical evidence for minimal vegetation change in peatlands of the West Siberian Lowland during the Medieval Climate Anomaly and Little Ice Age: Journal of Geophysical Research: Biogeosciences, 119(5), p. 808-825, illus. incl. 4 tables, 68 ref., May 2014.

Peatland vegetation is controlled primarily by the depth of the water table, making peat paleovegetation a useful climate archive. We applied a biochemical approach to quantitatively estimate the plant sources of peat carbon based on (1) neutral sugar compositions of Sphagnum, vascular plants, and lichens and (2) lignin phenol compositions of vascular plants. We used these biochemical indices to characterize vegetation change over the last 2000 years in four peat cores from the West Siberian Lowland (Russia) to investigate climate change during the Medieval Climate Anomaly and Little Ice Age. The vegetation was dominated by Sphagnum in all four cores, but was punctuated by several rapid but transient transitions to vascular plant dominance in the two cores from the southern West Siberian Lowland (<60°N latitude). Lichen contributions were evident at the end of the Medieval Climate Anomaly and during the Little Ice Age in the two cores from northern West Siberian Lowland (>60°N), possibly indicating permafrost development. However, there was no evidence for sustained vegetation change in response to either climatic event in cores from southern West Siberian Lowland. This suggests that these climatic events were relatively mild in the southern West Siberian Lowland, although the sensitivity of bog plant communities to climate change remains poorly understood. Abstract Copyright (2014), American Geophysical Union. All Rights Reserved.

DOI: 10.1002/2013JG002396

16006014 Lai Yuanming (Chinese Academy of Sciences, State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China); Pei Wansheng and Yu Wenbing. Calculation theories and analysis methods of thermodynamic stability of embankment engineering in cold regions: Chinese Science Bulletin, 59(3), p. 261-272, 40 ref., January 2014.

The calculation theories and analysis methods of thermodynamic stability of embankment engineering in cold regions are systematically summarized. The engineering theories and methods taken to control frost heave and thaw settlement in seasonal frozen soil regions may not be applicable in permafrost regions. The active cooling technology of roadbed should be utilized to limit the effects caused by both climate changes and human engineering activities. The paper mainly discussed the calculation theories and analysis methods of four kinds of embankment structures, i.e., the crushed-rock embankment, duct-ventilated embankment, thermosyphon embankment, and composite embankment. It is expected that a scientific basis could be provided for the theory, design, and application of embankment constructions in cold regions. Copyright 2013 Science China Press and Springer-Verlag Berlin Heidelberg

DOI: 10.1007/s11434-013-0012-9

16006392 Levy, Joseph S. (Oregon State University, College of Earth, Ocean and Atmospheric Sciences, Corvallis, OR); Fountain, Andrew G.; Gooseff, Michael N.; Barrett, J. E.; Vantreese, Robert; Welch, Kathy A.; Lyons, W. Berry; Nielsen, Uffe N. and Wall, Diana H. Water track modification of soil ecosystems in the Lake Hoare basin, Taylor Valley, Antarctica: Antarctic Science, 26(2), p. 153-162, illus. incl. 3 tables, 39 ref., 2014.

Water tracks are zones of high soil moisture that route shallow groundwater down-slope, through the active layer and above the ice table. A water track in Taylor Valley, McMurdo Dry Valleys, was analysed for surface hydrogeological, geochemical, and biological characteristics in order to test the hypothesis that water tracks provide spatial structure to Antarctic soil ecosystems by changing the physical conditions in the soil environment within the water tracks from those outside the water tracks. The presence of the water track significantly affected the distribution of biotic and abiotic ecosystem parameters: increasing soil moisture, soil salinity, and soil organic matter within the water track relative to soils outside the water track, and reducing soil phosphate, soil pH, and the population of nematodes and other invertebrates in water track soils relative to off track soils. These results suggest that water tracks are distinct and extreme ecological zones in Taylor Valley that provide long-range (kilometre to multi-kilometre) structure to Antarctic hillslope ecosystems through physical control on soil moisture and solute content. Contrary to expectations, these high soil-moisture sites are not hotspots for faunal biological activity because high soil salinity makes them suitable habitats for only the most halo-tolerant organisms.

DOI: 10.1017/S095410201300045X

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16001644 Rydzy, Marisa B. The effect of hydrate formation on the elastic properties of unconsolidated sediment: 172 p., illus. incl. 9 tables, geol. sketch maps, 142 ref., Doctoral, 2014, Colorado School of Mines, Golden, CO.

Natural gas hydrates exist in unconsolidated marine or permafrost sediments and can adopt many morphologies. Hydrates can occur in shapes of nodules, veins, layers, or finely disseminated between sediment grains. In the latter configuration, hydrate may cement sediment grains, act as a load-bearing sediment component, or occur free-floating in the pore fluid. While the sediment lithology dictates whether hydrate is present in massive or disseminated form, the manner of hydrate formation determines whether the disseminated hydrate will act as a cementing or non-cementing element in the system. The physical properties imparted to the hydrate-bearing sediment by hydrate can vary dramatically depending on how the hydrate forms, and in nature, gas hydrates generally form from gas dissolved in water, but can also form from water in the presence of a free gas phase. In this study, the effect of hydrate formation on the wave velocities of unconsolidated sediment was investigated in a series of laboratory studies, with particular focus on the extent to which the initial water saturation controls the manner in which hydrate is distributed, and thus the extent to which hydrate formation increases the wave velocity in sands. Ultrasonic p- and s-wave velocities (Vp, Vs) were measured in conjunction with magnetic resonance imaging (MRI) in hydrate-bearing Ottawa Sand F110 during hydrate formation and dissociation. Vp and Vs were determined as functions of gas hydrate saturation (Sh). Hydrates were formed out of solution using tetrahydrofuran (THF) and through CH₄ injection into partially water-saturated samples. For the latter, samples with low and high initial water saturation (Swi) were tested. The recorded velocities exhibited a noticeable dependence on Swi. At low Swi (~20%) the hydrate stiffened the sediment and increased the ultrasonic velocities dramatically. However, the rate at which the velocity increased during hydrate formation decreased with increasing Swi and small changes in the initial water saturation resulted in significant changes in final velocities. At high Swi (~80%), the velocity increased almost linearly with increasing hydrate content even at very low Sh. This behavior differed from that observed for hydrate formed out of solution. Ultrasonic velocities recorded in water-saturated, THF hydrate-bearing sand sediment did not change until a critical hydrate saturation of 35-50 percent was exceeded. Comparing measured velocities to those calculated with existing rock physics models links the initial water saturation, which determines the gas-water distribution in the sediment and hence the location of initial hydrate formation, to the evolution of wave velocity during hydrate formation. We concluded that at low Swi, the water is evenly distributed and located at the grain contacts. The resulting hydrate cements the grains, dramatically increasing the wave velocities even at low hydrate saturations. At high Swi, gas occurs in stiff bubbles within the pore space. The resulting hydrate particles become load-bearing and keep the grains from slipping. At intermediate Swi, gas and water appear to occur as patches, resulting in a mixture of load-bearing and cementing hydrate. The model comparison also reinforces our picture of hydrate-formation out of solution, where the pore-filling hydrate particles do not interact with the sediment until a critical value for Sh is exceeded and the hydrate becomes load-bearing. To test the dependence of the initial water distribution on the initial water saturation, micro X-ray CT images were also acquired of partially saturated glass-bead packs without hydrate but with varying amounts of water. At low water saturations, water occurred as bridges between adjacent glass beads or was located at the glass-bead contacts. At high water saturations, water occurred as a continuous phase and gas was present in the form of bubbles or patches. At intermediate water saturations both types of water distributions, gas bubbles and water bridges, were observed within one sample. With decreasing Swi, the closer the gas/water interface is located to the grain contact, the higher the degree of cementation will be when hydrate forms. Conversely, the higher the Swi the less cementation occurs and the less a given degree of hydrate formation will affect vp and vs in unconsolidated sediments. To extend our observations to hydrate-bearing systems, the distribution of THF and cyclopentane (CP) hydrate packs of glass beads was observed with micro X-ray computed tomography (CT). While THF is completely miscible in water, CP and water coexist as two separate phases. After hydrate formation in the THF hydrate-bearing samples, unconverted water was identified at the grain contacts and was often observed as a thin layer between hydrate and the glass-beads, indicating that the hydrate formation from the dissolved phase had initiated away from the glass beads and the bead-to-bead contacts. In some areas, THF hydrates grew to become amorphous patches that surrounded grains, but in most cases the hydrate was restricted to individual pores and exhibited characteristically sharp edges. In the CP hydrate-bearing samples, the image contrast between water/ice and CP hydrate could not be resolved. However, it appeared as if CP hydrate had formed along the CP-water interface and served as a diffusion barrier between the two phases. As hydrate in known to initially grow at the gas-water interface, the hydrate distribution was most likely affected by the distribution of water prior to hydrate formation. Based on the experimental results and our comparison with rock-physics theory, a conceptual model of hydrate in sediment was developed. The distribution of hydrate can be shown to be primarily a function of the water distribution within the sample prior to hydrate formation. With increasing water content, the distribution of the liquid phase transitions from being located at the grain contacts, to forming patchy networks, and finally becoming the continuous phase. When gas occurs as the continuous phase, hydrate grows into the water phase and the resulting hydrate will cement sediment grains. If water is the continuous phase, hydrate will grow into the gas phase and the resulting hydrate will initially be pore filling, but will become patchy and load-bearing as the hydrate saturation grows beyond 35-50% of the pore space.

URL: http://hdl.handle.net/11124/356

16000984 Walker, Laurel Anne. Determining hillslope diffusion rates in a boreal forest; Quaternary fluvial terraces in the Nenana River valley, central Alaska Range: 86 p., illus. incl. 7 tables, geol. sketch maps, 65 ref., Master, 2014, University of Kentucky, Lexington, KY.

The subarctic boreal forest biome is predicted to experience higher magnitudes of warming than other biomes due to climate change. The effects of this warming will be pronounced in areas underlain by discontinuous permafrost where melting permafrost and distinct changes in vegetation patterns are expected. To better understand rates of hillslope diffusion in the boreal forest I have used a geomorphic process modeling approach, using data from a sequence of Quaternary fluvial terraces located in the Nenana River valley of central Alaska. I hypothesized that diffusion rates here would be slower when compared to the mid-latitudes, and faster on north versus south-facing slopes. Calculated diffusion rates do support the hypothesis as they fall on the lower end of the global spectrum of documented hillslope diffusion rates. However, a significant difference in diffusion rates is not seen between the predominantly northeast and southwest facing slopes used in this study.

URL: http://uknowledge.uky.edu/ees_etds/16/

16001787 Matzke, Jeffrey Alan. Geophysical investigation of the stone zone and loamy mantle on the Iowan surface: 126 p., illus. incl. 11 tables, 41 ref., Master's, 2013, University of Iowa, Iowa City, IA.

The processes that generated the distinctive landscape of the Iowa Erosion Surface (IES) of northeastern Iowa have been debated for over a century. A number of researchers have concluded that the IES experienced a periglacial environment and was underlain by continuous permafrost during the last glacial maximum. Ubiquitous throughout the IES is a stone zone that lies 60-100 cm below the surface. Several explanations for the genesis of the stone zone have been proposed, including a lag concentrate, biomantle processes, and cryogenesis. We utilized a combination of coring and trenching, ground penetrating radar and resistivity to investigate the 3D distribution of the stone zone, overlying "pedisediment" and the underlying contact with dense till across a 100 m² area on a typical IES hillslope in east-central Iowa. Our preliminary results indicate that the stone zone occurs in the basal few decimeters of pedisediment that rests uncomformably and abruptly on eroded, dense till. Ice wedge casts extend from the stone zone into the underlying till. The depth of the stone zone below the modern surface increases downslope and the stone zone dissipates and eventually is replaced by relatively thick loamy sand beneath the footslope. These relationships argue against the stone zone being of biogenic origin. The occurrence of ice wedge casts associated with the stone zone and systematic changes in the thickness and texture of the pedisediment suggest to us that stone zone on the IES was formed by a combination of cryogenic and active zone erosive processes during the full glacial period.

URL: http://ir.uiowa.edu/etd/5022/

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16003554 Arenson, Lukas U. (BGC Engineering, Vancouver, BC, Canada); Johnston, Katherine; Quinn, Pete and Wainstein, Pablo. Considering permafrost in the design of linear infrastructure through mountainous terrain: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch maps, 29 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16003560 Lacelle, Denis (University of Ottawa, Department of Geography, Ottawa, ON, Canada); Fontaine, Marielle and Kokelj, Steve V. Geochemistry of the active layer and permafrost in northwestern Canada; from measurements to Quaternary stratigraphy: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus., 35 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16003589 Milanovskiy, Svet (Russian Academy of Sciences, Institute Physics of the Earth, Moscow, Russian Federation); Velikin, Sergey; Petruin, Alexey and Istratov, Vyatcheslav. Geophysical monitoring of engineering construction in western Yakutia and study of coupled problem of temperature and seepage fields in permafrost near hydro unit: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 12 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16003592 Oldenborger, Greg A. (Geological Survey of Canada, Ottawa, ON, Canada); LeBlanc, Anne-Marie; Stevens, Chris W.; Chartrand, Jason and Loranger, Benoit. Geophysical imaging of permafrost conditions along the northern Yukon Alaska Highway: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 20 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16003557 Phillips, M. R. (Carleton University, Department of Geography and Environmental Studies, Ottawa, ON, Canada); Burn, C. R.; Wolfe, S. A.; Morse, P. D.; Gaanderse, A. J.; O'Neill, H. B.; Shugar, D. H. and Gruber, S. Improving water content description of ice-rich permafrost soils: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, 24 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16003591 Pumple, Joel (University of Alberta, Edmonton, AB, Canada); Froese, Duane and Calmels, Fabrice. Characterizing permafrost valley fills along the Alaska Highway, southwest Yukon: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, 32 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16003558 Wang Yongping (Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Laboratory of Frozen Soils Engineering, Lanzhou, China); Jin Huijun; Hao Jiaqian; Li Guoyu; Cai Yongjun and He Shusheng. Pipe-laying technology in a subarctic permafrost region; a case study for the China-Russia crude oil pipeline from Mo'he to Daqing, northern northeast China: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 19 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16003590 Way, Robert G. (University of Ottawa, Department of Geography, Ottawa, ON, Canada) and Lewkowicz, Antoni G. Investigations of discontinuous permafrost in coastal Labrador with DC electrical resistivity tomography: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 34 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16003126 Bliss, Andrew K. (University of Alaska Fairbanks, Department of Natural Resources, Fairbanks, AK); Hock, Regine; Wolken, Gabriel J.; Zhang, Jing; Whorton, Erin; Braun, Juliana Louisa; Gusmeroli, Alessio; Liljedahl, Akli and Schulla, J. Twenty-first century changes in the hydrology, glaciers, and permafrost of the Susitna Basin, Alaska [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract H43J-1092, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

In the face of climate change, the hydrology of the upper Susitna Basin in South-Central Alaska is expected to change. This would impact the quantity and seasonality of river flow into a proposed hydroelectric dam, if it were to be built. The upper Susitna Basin catchment area is 13,289 km², ranging from 450-4000 m a.s.l. It is 4% glacierized and is characterized by sparse vegetation, discontinuous permafrost, and little human development. We present field measurements and results from hydrological modeling. We present new field data from spring and fall 2014 along with field measurements from the 1980's, 2012, and 2013. These data are used to calibrate and validate the hydrological model. Traditional glacier mass balance measurements show that the glaciers lost more mass in 2012 and 2013 than in 1981, 1982, or 1983. Springtime snow radar surveys of the glaciers allow us to extrapolate from point measurements of snow depth to the whole glacier area. Snow depth measurements at tundra sites as well as tundra vegetation and soil characterizations help us choose appropriate model parameters for the tundra portions of the basin. Meteorological data (temperature, humidity, and precipitation) from over 20 stations in the basin show the summertime temperature lapse rate to be smaller over glacier surfaces compared to ice-free surfaces. Precipitation is highly variable across the basin. Energy balance measurements from two meteorological stations, one located on West Fork Glacier and one on a nunatak near Susitna Glacier, are used for more detailed modeling of summertime glacier melt and runoff. We run a physically-based hydrological model to project 21st century river discharge: Water Flow and Balance Simulation Model (WaSiM). Climate inputs come from a CCSM CMIP5 RCP6.0 scenario downscaled to a 20 km-5 km nested grid using the Weather Research and Forecasting (WRF) Model. From 2010-2029 to 2080-2099 the basin-wide mean-annual temperature will rise 2.5 degrees and total precipitation will rise 2%, with a 13% decrease in snowfall and a 20% increase in rainfall. Preliminary WaSiM runs indicate that glaciers will retreat, evapotranspiration will increase, and permafrost will thaw. Annual runoff will remain relatively steady, but the timing of the peak spring runoff will shift to an earlier date.

16003559 Nelson, Frederick E. (Northern Michigan University, Department of Earth, Enviornmental and Geographical Sciences, Marquette, MI) and Schimek, Melanie A. Topoclimatic controls on active-layer thickness, Alaskan Coastal Plain: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. 1 table, sketch map, 19 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16003588 Sadurtdinov, M. r. (Russian Academy of Sciences, Siberian Branch, Earth Cryosphere Institute, Moscow, Russian Federation); Tsarev, A. M.; Skvortsov, A. G. and Sudakova, M. S. Seismic studies of frozen ground in Russian Arctic areas: in 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015 (Côté, Jean, chairperson; et al.), Canadian Geotechnical Conference = Conference Canadienne de Géotechnique, 68, unpaginated (French sum.), illus. incl. sketch map, 12 ref., 2015. Meeting: 68th Canadian geotechnical conference and 7th Canadian permafrost conference; GEOQuébec 2015, Sept. 20-23, 2015, Quebec City, QC, Canada.

16006197 Deusner, C. (GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany); Bigalke, N. K.; Kossel, E. and Haeckel, M. Studies towards the development of a CH₄ production technology by CO₂ sequestration into submarine hydrate reservoirs [abstr.]: in 75th EAGE conference & exhibition incorporating SPE EUROPEC 2013, Conference and Technical Exhibition - European Association of Geoscientists and Engineers, 75, Abstract We 04 14, illus., 7 ref., 2013. Meeting: 75th EAGE conference & exhibition incorporating SPE EUROPEC 2013, June 10-13, 2013, London, United Kingdom.

In the recent past, international research efforts towards exploitation of submarine and permafrost hydrate reservoirs have increased substantially. Emission neutral exploitation of CH4-hydrates could potentially be achieved in a combined process with CO2 injection and storage as CO2-hydrate. In the German gas hydrate initiative SUGAR, a combination of experimental and numerical studies is used to elucidate the process mechanisms and technical parameters on different scales. Among the parameters tested so far are the CO2 injection regime, the injection temperature and the reservoir pressure/temperature conditions. It was shown that CH4 production is optimal at intermediate reservoir temperatures (8°C) compared to lower (2°C) and higher temperatures (10°C). The reservoir pressure, however, was of minor importance for the production efficiency. The injection of heated CO2 into the hydrate reservoir induces a variety of spatial and temporal processes which result in substantial bulk heterogeneity. Current numerical simulators are not able to predict these process dynamics and it is important to improve available transport-reaction models. Our results confirm that experimental studies are important to better understand the mechanisms of hydrate dissociation and conversion at CO2-injection conditions as a basis towards the development of a suitable hydrate conversion technology.

DOI: 10.3997/2214-4609.20130743

16001363 Wlostowski, Adam N. (Colorado State University, Fort Collins, CO); Gooseff, M. N. and McKnight, Diane M. How do hyporheic zones mediate stream solute loads? Using Antarctic glacial melt streams to simplify the problem [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract H23Q-06, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

The McMurdo Dry Valleys of Antarctica are one of the coldest and driest places on earth. This polar desert provides a simple hydrologic system, where seasonally intermittent streams convey glacier melt water into closed basin lakes. Streams are underlain by continuous permafrost, but during the flow season a thawed hyporheic zone (<1m) develops around the open channel. The exchange of relatively dilute glacier water with hyporheic sediments facilitates weathering processes that control stream solute loads. This study uses several end-member mixing models to simulate concentration - discharge relationships observed in 14 streams, using over 20 years of hydro chemical data. Results show that (1) streams exhibit chemostatic behavior across daily and annual timescales, indicating a temporally variable flux of solutes from the hyporheic zone; (2) the chemical budgets of longer streams are more influenced by hyporheic zone reactions than shorter streams; and (3) end-member mixing models and naturally occurring tracers allow for the passive modeling of hyporheic exchange processes. This work provides insight into how weathering contributions from hyporheic zones affect catchment ionic budgets in diverse temperate and polar catchments with dilute snow and glacial meltwater sources of streamflow.

16003098 Abban, B. K. (University of Tennessee, Knoxville, TN); Papanicolaou, T.; Wacha, Kenneth and Wilson, C. G. A GIS-based framework for examining the effects of water-driven erosion on soil biogeochemical cycling [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract H43D-0987, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Soil erosion has long been identified as one of the key mechanisms affecting biogeochemical processes in the soil, through the transport and delivery of carbon and nutrients adsorbed to soil particles in the soil active layer. However, most biogeochemical models treat soil erosion contributions simplistically and lack the capacity to accurately account for the mechanisms that control soil erosion and deposition on the landscape. This stems from the fact that the majority of the biogeochemical models have traditionally been employed on landscapes where lateral and downslope fluxes due to soil erosion have been less significant compared to other vertical fluxes and processes occurring at a fixed location on the landscape. In intensely managed landscapes, however, this may not be the case since land management practices such as tillage and exposed land cover can lead to copious amounts of erosion on the landscape. Therefore, to better understand the role of soil erosion on soil biogeochemical cycling in IMLs, we present a framework for simulating the spatiotemporal effects of soil erosion and deposition on soil biogeochemical cycling. We focus specifically on tillage- and runoff-induced erosion since these are prevalent in IMLs. The framework employs a geospatial approach that loosely couples a GIS-based upland water erosion model, GeoWEPP, with a soil biogeochemistry model, Century, to predict downslope and lateral fluxes of soil erosion and the resultant impacts on soil biogeochemical cycling. The use of a geospatial approach allows us to better capture the effects of topography, soil type, land use/land cover, and climate on soil erosion fluxes as well as soil biogeochemical cycling. The spatiotemporal resolution of the framework makes it particularly beneficial for identifying hotspots in fields and hot moments at scales ranging from daily to annual time scales. We employ the framework to study the monthly redistribution of soil organic carbon over the course of a year in the South Amana Sub-Watershed, located in the headwaters of Clear Creek, Iowa, USA. Preliminary results indicate that the framework is able to capture observed erosional and depositional patterns in the watershed and can provide insight into soil carbon redistribution and sequestration.

16003133 Ganji, Arman (University of Quebec at Montreal, Montreal, QC, Canada) and Sushama, L. On the frozen soil scheme for high latitude regions [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract H43J-1109, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Regional and global climate model simulated streamflows for high-latitude regions show systematic biases, particularly in the timing and magnitude of spring peak flows. Though these biases could be related to the snow water equivalent and spring temperature biases in models, a good part of these biases is due to the unaccounted effects of non-uniform infiltration capacity of the frozen ground and other related processes. In this paper, the frozen scheme in the Canadian Land Surface Scheme (CLASS), which is used in the Canadian regional and global climate models, is modified to include fractional permeable area, supercooled liquid water and a new formulation for hydraulic conductivity. Interflow is also included in these experiments presented in this study to better explain the steamflows after snow melt season. The impact of these modifications on the regional hydrology, particularly streamflow, is assessed by comparing three simulations, performed with the original and two modified versions of CLASS, driven by atmospheric forcing data from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data (ERA-Interim), for the 1990-2001 period, over a northeast Canadian domain. The two modified versions of CLASS differ in the soil hydraulic conductivity and matric potential formulations, with one version being based on formulations from a previous study and the other one is newly proposed. Results suggest statistically significant decreases in infiltration for the simulation with the new hydraulic conductivity and matric potential formulations and fractional permeable area concept, compared to the original version of CLASS, which is also reflected in the increased spring surface runoff and streamflows in this simulation with modified CLASS, over most of the study domain. The simulated spring peaks and their timing in this simulation is also in better agreement to those observed.

16001509 Wacha, Kenneth (University of Iowa, Hydroscience & Engineering, Iowa City, IA); Papanicolaou, T.; Abban, B. K. and Wilson, C. G. Potential carbon transport; linking soil aggregate stability and sediment enrichment for updating the soil active layer within intensely managed landscapes [abstr.]: in AGU 2014 fall meeting, American Geophysical Union Fall Meeting, 2014, Abstract H42C-04, December 2014. Meeting: American Geophysical Union 2014 fall meeting, Dec. 15-19, 2014, San Francisco, CA.

Currently, many biogeochemical models lack the mechanistic capacity to accurately simulate soil organic carbon (SOC) dynamics, especially within intensely managed landscapes (IMLs) such as those found in the U.S. Midwest. These modeling limitations originate by not accounting for downslope connectivity of flowpathways initiated and governed by landscape processes and hydrologic forcing, which induce dynamic updates to the soil active layer (generally top 20-30 cm of soil) with various sediment size fractions and aggregates being transported and deposited along the downslope. These hydro-geomorphic processes, often amplified in IMLs by tillage events and seasonal canopy, can greatly impact biogeochemical cycles (e.g., enhanced mineralization during aggregate breakdown) and in turn, have huge implications/uncertainty when determining SOC budgets. In this study, some of these limitations were addressed through a new concept, Potential Carbon Transport (PCT), a term which quantifies a maximum amount of material available for transport at various positions of the landscape, which was used to further refine a coupled modeling framework focused on SOC redistribution through downslope/lateral connectivity. Specifically, the size fractions slaked from large and small aggregates during raindrop-induced aggregate stability tests were used in conjunction with rainfall-simulated sediment enrichment ratio (ER) experiments to quantify the PCT under various management practices, soil types and landscape positions. Field samples used in determining aggregate stability and the ER experiments were collected/performed within the historic Clear Creek Watershed, home of the IML Critical Zone Observatory, located in Southeastern Iowa.

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16005235 Riedel, M.; Ulmi, M.; Conway, K. W.; Standen, G.; Rosenberger, A.; Hong, J. K.; Jin, Y. K.; Kim, H. S. and Dallimore, S. R. Ocean bottom seismometer experiment on the Beaufort shelf and slope region conducted during Expedition ARA04C on the IBRV Araon: Open-File Report - Geological Survey of Canada, Rep. No. 7621, 64 p., illus. incl. tables, 2015. Revised edition. This publication supercedes Geological Survey of Canada Open-File Report No. 7621, 2014.

Expedition ARA04C (conducted from September 10 - September 26, 2013 in Canadian waters) on the Korean icebreaker IBRV Araon was laid out to investigate the Beaufort Sea shelf and slope region and collect geo-scientific data for various aspects relevant to the GSC's mandated regional geo-hazard assessment of the offshore Beaufort region. A critical element of the geohazards is the distribution of permafrost across the submerged shelf. To address this question a set of six Ocean Bottom Seismometers (OBS) were deployed in a grid pattern across the near shelf-edge zone, and a set of three OBS was used in a second deployment along a central shelf crossing north-east to south-west oriented line. Initial data processing was carried out, which is required for any follow-up detailed velocity analysis. The processing included definition of exact shot times, geometry calculation, OBS position re-location, and OBS orientation analysis. A preliminary analysis of the hydrophone and vertical-component data from the OBS stations reveals a P-wave-velocity structure with values ranging from 1800 m/s to over 4000 m/s indicative of wide-spread ice-bearing sediments. This open-file report also contains the digital OBS data for all stations in standard SEGY format, together with the required raw and processed geometry information.

DOI: 10.4095/295550

16002990 Chartrand, J.; Ednie, M.; Smith, S. L.; Duchesne, C. and Riseborough, D. W. Report on 2013 field activities and collection of ground thermal and active layer data in the Mackenzie Corridor: Open-File Report - Geological Survey of Canada, Rep. No. 7659, 105 p., illus. incl. tables, 15 ref., 2014.

This report presents a summary of field activities conducted in 2013 in the Mackenzie corridor, N.W.T. Air temperature, ground thermal and active layer data acquired from permafrost monitoring sites visited in 2013 throughout the corridor are provided in graphical and tabular format. The data presented provide essential baseline information that can be utilized by stakeholders and others for various purposes such as land management activities, regulatory processes and design of northern infrastructure. This report will be distributed to community organizations and stakeholders in the study region to provide an update on field activities.

DOI: 10.4095/295596

16002981 Riedel, M. (Geological Survey of Canada, Sidney, BC, Canada); Hong, J. K.; Jin, Y. K. and Kim, H. S. Refraction seismic velocity analyses from multichannel seismic data acquired during Expedition ARA04C on the IBRV Araon in the Beaufort Sea: Open-File Report - Geological Survey of Canada, Rep. No. 7618, 67 p., illus. incl. tables, 4 ref., 2014.

Expedition ARA04C (conducted from September 10 - September 26, 2013 in Canadian waters) on the Korean icebreaker IBRV Araon was laid out to investigate the Beaufort Sea shelf and slope region and collect geo-scientific data for various aspects relevant to the GSC's mandated regional geohazard assessment of the offshore Beaufort region. A critical element of the geohazards is the distribution of permafrost across the submerged shelf. To address this question and to verify data from earlier attempts made by the GSC in the mid 1980s, a set of multichannel seismic (MCS) lines were collected across and along the shelf edge. Refracted arrivals were picked on all MCS lines acquired and velocities for the first and where occurring, second and even third refractions were determined. The depth to the first refractor was determined using simple ray-path geometry for a refracted, planar 2 layer case, with a fixed velocity of the upper layer (ocean water) of 1450 m/s determined from measurements of physical properties in the water column using a standard Conductivity-Temperature-Depth (CTD) tool. Using this velocity value creates a fully flat direct arrival when the shot-gather is reduced by this velocity value, confirming that this value is appropriate. Depths to 2nd or 3rd refractor where not determined in this study. Arrivals from deeper refractions are often masked by the occurrence of refractions generated by multiples and from strong linear noise occurring along the streamer. The results from the refraction velocity analysis allow verification of major boundaries of permafrost or ice-bearing sediment occurrences from previous work, but also define several critical corrections, especially near the shelf edge zone. Correlation of the MCS refraction data and the coincident 3.5 kHz sub-bottom profiler data reveal that a regional unconformity (5 to 15 meter below seafloor) often is the source of the first detectable refraction instead of the seafloor.

DOI: 10.4095/295549

16002982 Riedel, M. (Geological Survey of Canada, Sidney, BC, Canada); Ulmi, M.; Conway, K. W.; Standen, G.; Rosenberger, A.; Hong, J. K.; Jin, Y. K.; Kim, H. S. and Dallimore, S. R. Ocean bottom seismometer experiment on the Beaufort shelf and slope region conducted during Expedition ARA04C on the IBRV Araon: Open-File Report - Geological Survey of Canada, Rep. No. 7621, 55 p., illus. incl. tables, 2014.

Expedition ARA04C (conducted from September 10 - September 26, 2013 in Canadian waters) on the Korean icebreaker IBRV Araon was laid out to investigate the Beaufort Sea shelf and slope region and collect geo-scientific data for various aspects relevant to the GSC's mandated regional geo-hazard assessment of the offshore Beaufort region. A critical element of the geohazards is the distribution of permafrost across the submerged shelf. To address this question a set of six Ocean Bottom Seismometers (OBS) were deployed in a grid pattern across the near shelf-edge zone, and a set of three OBS was used in a second deployment along a central shelf-crossing north-east to south-west oriented line. Initial data processing was carried out, which is required for any follow-up detailed velocity analysis. The processing included definition of exact shot times, geometry calculation, OBS position re-location, and OBS orientation analysis. A preliminary analysis of the hydrophone and vertical-component data from the OBS stations reveals a P-wave-velocity structure with values ranging from 1800 m/s to over 4000 m/s indicative of wide-spread ice-bearing sediments. This open-file report also contains the digital OBS data for all stations in standard SEGY format, together with the required raw and processed geometry information.

DOI: 10.4095/295550

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