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At least 1,225 records · Page 68Linked to original sources
USGS1994

Roughness coefficients for high-gradient channels in New York State

Manning's roughness coefficients (n values) were computed for a range of flows at six streams in New York State (USA) that have high energy gradients (greater than 0.002) and large median bed-particle sizes (between 0.14 and 0.36 meters). The coefficients, which ranged from 0.034 to 0.061 for bankfull flows, were computed from discharges, channel geometry, and water-surface profiles measured at each of the sites. An inverse relation between the n values and flow depth (or hydraulic radius) was evident at five sites. The roughness coefficient decreases rapidly with increasing depth and approaches an asymptotic value as bankfull flow is approached. At individual sites, the slope (water-surface slope and energy gradient) generally increases with increasing flow depth and is inversely related to the n value. Among the sites, however, the roughness coefficient and slope show a direct relation. The near-bankfull n values on channels with slopes between 0.008 and 0.014 were generally in the range of 0.05 to 0.06, whereas those on channels with lower slopes, between 0.004 and 0.005, were in the 0.03-to-0.04 range. Streambank vegetation has a measurable effect on the computed n values at two of the sites. Dense vegetation on one side of the medium-flow channel on Beaver Kill at Cooks Falls interrupts the decreasing trend in the roughness coefficient as the water level rises and produces higher-than-expected n values up to the point of vegetation submergence. The effects of streambank vegetation at Tremper Kill near Andes change seasonally; the n-value increases by as much as 0.012 from nongrowing to growing seasons. The effect of the vegetation decreases with increasing flow depth as a result of the decrease in energy losses as the vegetation becomes submerged and bends with the flow. Roughness coefficients, which were computed around 1950 for three of the study sites, are reasonably close to those computed in this study.

Conference Paper↗
USGS2000

Reevaluation of tsunami formation by debris avalanche at Augustine Volcano, Alaska

Debris avalanches entering the sea at Augustine Volcano, Alaska have been proposed as a mechanism for generating tsunamis. Historical accounts of the 1883 eruption of the volcano describe 6- to 9-meter-high waves that struck the coastline at English Bay (Nanwalek), Alaska about 80 kilometers east of Augustine Island. These accounts are often cited as proof that volcanigenic tsunamis from Augustine Volcano are significant hazards to the coastal zone of lower Cook Inlet. This claim is disputed because deposits of unequivocal tsunami origin are not evident at more than 50 sites along the lower Cook Inlet coastline where they might be preserved. Shallow water (<25 m) around Augustine Island, in the run-out zone for debris avalanches, limits the size of an avalanche-caused wave. If the two most recent debris avalanches, Burr Point (A.D. 1883) and West Island (<500 yr. B.P.) were traveling at velocities in the range of 50 to 100 meters per second, the kinetic energy of the avalanches at the point of impact with the ocean would have been between 1014 and 1015 joules. Although some of this energy would be dissipated through boundary interactions and momentum transfer between the avalanche and the sea, the initial wave should have possessed sufficient kinetic energy to do geomorphic work (erosion, sediment transport, formation of wave-cut features) on the coastline of lowwer Cook Inlet. Because widespread evidence of the effects of large waves cannot be found, it appears that the debris avalanches could not have been traveling very fast when they entered the sea, or they happened during low tide and displaced only small volumes of water. In light of these results, the hazard from volcanigenic tsunamis from Augustine Volcano appears minor, unless a very large debris avalanche occurs at high tide.

Pure and Applied Geophysics↗
USGS2003

The history and development of FETAX (ASTM standard guide, E-1439 on conducting the frog embryo teratogenesis Assay-Xenopus)

The energy crisis of the 1970's and 1980's prompted the search for alternative sources of fuel. With development of alternate sources of energy, concerns for biological resources potentially adversely impacted by these alternative technologies also heightened. For example, few biological tests were available at the time to study toxic effects of effluents on surface waters likely to serve as receiving streams for energy-production facilities; hence, we began to use Xenopus laevis embryos as test organisms to examine potential toxic effects associated with these effluents upon entering aquatic systems. As studies focused on potential adverse effects on aquatic systems continued, a test procedure was developed that led to the initial standardization of FETAX. Other .than a limited number of aquatic toxicity tests that used fathead minnows and cold-water fishes such as rainbow trout, X. laevis represented the only other aquatic vertebrate test system readily available to evaluate complex effluents. With numerous laboratories collaborating, the test with X. laevis was refined, improved, and developed as ASTM E-1439, Standard Guide for the Conducting Frog Embryo Teratogenesis Assay-Xenopus (FETAX). Collabrative work in the 1990s yielded procedural enhancements, for example, development of standard test solutions and exposure methods to handle volatile organics and hydrophobic compounds. As part of the ASTM process, a collaborative interlaboratory study was performed to determine the repeatability and reliability of FETAX. Parallel to these efforts, methods were also developed to test sediments and soils, and in situ test methods were developed to address "lab-to-field extrapolation errors" that could influence the method's use in ecological risk assessments. Additionally, a metabolic activation system composed of rat liver microsomes was developed which made FETAX more relevant to mammalian studies.

Conference Paper↗
USGS2004

Geothermal resources of California sedimentary basins

The 2004 Department of Energy (DOE) Strategic Plan for geothermal energy calls for expanding the geothermal resource base of the United States to 40,000 MW of electric power generating potential. This will require advances in technologies for exploiting unconventional geothermal resources, including Enhanced Geothermal Systems (EGS) and geopressured geothermal. An investigation of thermal conditions in California sedimentary basins through new temperature and heat flow measurements reveals significant geothermal potential in some areas. In many of the basins, the combined cooling effects of recent tectonic and sedimentary processes result in relatively low (<60 mW/m2) heat flow and geothermal gradients. For example, temperatures in the upper 3 km of San Joaquin, Sacramento and Ventura basins are typically less than 125??C and do not reach 200??c by 5 km. By contrast, in the Cuyama, Santa Maria and western Los Angeles basins, heat flow exceeds 80 mW/m2 and temperatures near or above 200??C occur at 4 to 5 km depth, which represents thermal conditions equivalent to or hotter than those encountered at the Soultz EGS geothermal site in Europe. Although the extractable geothermal energy contained in these basins is not large relative to the major California producing geothermal fields at The Geysers or Salton Sea, the collocation in the Los Angeles basin of a substantial petroleum extraction infrastructure and a major metropolitan area may make it attractive for eventual geothermal development as EGS technology matures.

Conference Paper↗
USGS2005

Outstanding issues for new geothermal resource assessments

A critical question for the future energy policy of the United States is the extent to which geothermal resources can contribute to an ever-increasing demand for electricity. Electric power production from geothermal sources exceeds that from wind and solar combined, yet the installed capacity falls far short of the geothermal resource base characterized in past assessments, even though the estimated size of the resource in six assessments completed in the past 35 years varies by thousands of Megawatts-electrical (MWe). The U. S. Geological Survey (USGS) is working closely with the Department of Energy's (DOE) Geothermal Research Program and other geothermal organizations on a three-year effort to produce an updated assessment of available geothermal resources. The new assessment will introduce significant changes in the models for geothermal energy recovery factors, estimates of reservoir permeability, limits to temperatures and depths for electric power production, and include the potential impact of evolving Enhanced (or Engineered) Geothermal Systems (EGS) technology.

Conference Paper↗
USGS2012

Statistical analyses to support guidelines for marine avian sampling. Final report

Interest in development of offshore renewable energy facilities has led to a need for high-quality, statistically robust information on marine wildlife distributions. A practical approach is described to estimate the amount of sampling effort required to have sufficient statistical power to identify species-specific “hotspots” and “coldspots” of marine bird abundance and occurrence in an offshore environment divided into discrete spatial units (e.g., lease blocks), where “hotspots” and “coldspots” are defined relative to a reference (e.g., regional) mean abundance and/or occurrence probability for each species of interest. For example, a location with average abundance or occurrence that is three times larger the mean (3x effect size) could be defined as a “hotspot,” and a location that is three times smaller than the mean (1/3x effect size) as a “coldspot.” The choice of the effect size used to define hot and coldspots will generally depend on a combination of ecological and regulatory considerations. A method is also developed for testing the statistical significance of possible hotspots and coldspots. Both methods are illustrated with historical seabird survey data from the USGS Avian Compendium Database. Our approach consists of five main components: 1. A review of the primary scientific literature on statistical modeling of animal group size and avian count data to develop a candidate set of statistical distributions that have been used or may be useful to model seabird counts. 2. Statistical power curves for one-sample, one-tailed Monte Carlo significance tests of differences of observed small-sample means from a specified reference distribution. These curves show the power to detect "hotspots" or "coldspots" of occurrence and abundance at a range of effect sizes, given assumptions which we discuss. 3. A model selection procedure, based on maximum likelihood fits of models in the candidate set, to determine an appropriate statistical distribution to describe counts of a given species in a particular region and season. 4. Using a large database of historical at-sea seabird survey data, we applied this technique to identify appropriate statistical distributions for modeling a variety of species, allowing the distribution to vary by season. For each species and season, we used the selected distribution to calculate and map retrospective statistical power to detect hotspots and coldspots, and map pvalues from Monte Carlo significance tests of hotspots and coldspots, in discrete lease blocks designated by the U.S. Department of Interior, Bureau of Ocean Energy Management (BOEM). 5. Because our definition of hotspots and coldspots does not explicitly include variability over time, we examine the relationship between the temporal scale of sampling and the proportion of variance captured in time series of key environmental correlates of marine bird abundance, as well as available marine bird abundance time series, and use these analyses to develop recommendations for the temporal distribution of sampling to adequately represent both shortterm and long-term variability. We conclude by presenting a schematic “decision tree” showing how this power analysis approach would fit in a general framework for avian survey design, and discuss implications of model assumptions and results. We discuss avenues for future development of this work, and recommendations for practical implementation in the context of siting and wildlife assessment for offshore renewable energy development projects.

NOAA Technical Memorandum↗
USGS2013

Bakken, Three Forks largest continuous US oil accumulation

The recent reversal of the declining trend of US oil production is largely due to production from unconventional or "continuous" low-permeability reservoirs by use of multistage hydraulic fracturing of horizontal legs of exploration wells. The US currently produces about 7.4 million bo/d, and the increasing trend in domestic production has led to speculation that the US could become energy independent in oil in the near future. The US still imports an additional 11 million bo/d to meet consumption requirements).1 Critical to the discussion of energy independence are estimates of resources contained in low-porosity and low-permeability (or "tight") continuous oil and gas accumulations, which have formed a critical component of national energy policies in recent years.

Montana, North Dakota, South Dakota, Wyoming↗
USGS1969

The geographic applications program of the U. S. Geological Survey

The fundamental objective of modern Geography is to improve man's level of living through a better understanding of man-environment inter actions. Related goals of the USGS program for applications of remote sensor data to Geographical research are: (1) the analysis and improvement of land use, with special emphasis on urban problems; and (2) more effective use of the total available energy budget, including insolation, mineral fuels, atomic energy, human resources, and mental energy, all of which are integrated into man-environment interactions. The collection of data through remote sensors in air craft and spacecraft is financed largely by funds from NASA, and is part of the much broader EROS Program of the Department of the Interior. Results to date have achieved much toward the identification of remote sensor signatures for Earth features and human activities, and toward evaluation of instruments for collecting essential information.

Photogrammetric Engineering↗
USGS1984

A workshop model simulating fate and effect of drilling muds and cuttings on benthic communities

Oil and gas exploration and production at marine sites has generated concern over potential environmental impacts resulting from the discharge of spent drilling muds and cuttings. This concern has led to a broad array of publicly and privately sponsored research. This report described a cooperative modeling effort designed to focus information resulting from this research through construction of explicit equations that simulate the potential impacts of discharge drilling fluids (muds) and cuttings on marine communities. The model is the result of collaboration among more than 30 scientists. The principal cooperating organizations were the E.S. Environmental Protection Agency, the U.S. Minerals Management Service, the Offshore Operators Committee, and the Alaska Oil and Gas Association. The overall simulation model can be conceptualized as three connected submodels: Discharge and Plume Fate, Sediment Redistribution, and Benthic Community Effects. On each day of simulation, these submodels are executed in sequence, with flows of information between submodels. The Benthic Community Effects submodel can be further divided into sections that calculate mortality due to burial, mortality due to toxicity, mortality due to resuspension disturbance, and growth of the community. The model represents a series of seven discrete 1-m 2 plots at specified distances along a transect in one direction away from a discharge point. It consists of coupled difference equations for which parameter values can easily be set to evaluate different conditions or to examine the sensitivity of output to various assumptions. Sets of parameter values were developed to represent four general cases or scenarios: (1) a shallow (5 m), cold environment with ice cover during a substantial fraction of the year, such as might be encountered in the Beaufort Sea, Alaska; (2) a shallow (20 m), temperate environment, such as might be encountered in the Gulf of Mexico; (3) a deeper (80 m), temperate environment, such as might be encountered in the Gulf of Mexico; and (4) a very deep (1,000 m) environment, such as might be encountered on the Atlantic slope. The focus of the modeling effort was on the connection of a reasonable representation of physical fate to the biological responses of populations, rather than on highly detailed representations of individual processes. For example, the calculations of physical fate are not as detailed as those in the recently published model of Brandsma et al. (1983). The value of the model described herein is in the broad scope of processes that are explicitly represented and linked together. The model cannot be considered to produce reliable predictions of the quantitative impacts of discharged drilling fluids and cuttings on biological populations at a particular site. Limitations of the model in predicting integrated fate and effects can be traced to three general areas: level of refinement of the algorithms used in the model; lack of understanding of the processes determining fate and effects; and parameter and data values. Despite the limitations, several qualitative conclusions concerning both potential impacts and the importance of various remaining data gaps can be drawn from the modeling effort. These include: (1) Simple, unequivocal conclusions about fate and effects across geographical regions and drilling operations are difficult, if not misleading, due to the large amount of variability in characteristics of discharged materials (e.g., oil content and toxicity), discharge conditions (e.g., duration of drilling operations), physical environments (e.g., water depth, current direction, and sediment disturbance regimes), and biological communities (e.g., intrinsic growth rates). Different combinations of these characteristics can result in substantial differences in simulated environmental fate and biological effects. For examples, simulated recovery in some high-energy environments occurs within months after the cessation of discharge operations, even at heavily impacted sites, whereas simulated recover in some low-energy environments takes years at heavily impacted sites. <2) Considerable difficulties remain in the reliable extrapolation of results from laboratory toxicity experiments to predictions of population effects in the field. (3) The volume of material discharged and duration of operations in the production drilling operations simulated by the model are sufficient to produce substantial simulated biological impacts at some plots, both in terms of differences from a control plot during the period of discharge operations, and in terms of the recovery period following the perturbations. Evaluation of the significance of potential effects involves the following factors: • Definition of a specific spatial and temporal reference frame (e.g., What is the natural variation? Is 1 year to be considered a "long" or "short" time? Is 50 m to be considered a "large" or "trivial" distance? • Consideration of rare or unique resources and particularly sensitive biotic assemblages. • Consideration of the potential for long term, cumulative effects. Some of these aspects are clearly beyond the scope of this modeling efforts (e.g., the model does not simulate the long term fate of resuspended material). The model does, however, contain an internal "reference frame" by comparison to simulated behavior at a control plot. The model, in general, simulates substantial "natural" variation at the reference or control plots, both over time, due to sediment disturbance events in medium to high energy environments, and over space, due to geographically varying conditions, such as water depth and current regime.

Report↗
USGS2013

Ecosystem stressors in southern Nevada

Southern Nevada ecosystems and their associated resources are subject to a number of global and regional/local stressors that are affecting the sustainability of the region. Global stressors include elevated carbon dioxide (CO 2 ) concentrations and associated changes in temperature and precipitation patterns and amount, solar radiation, and nutrient cycles (Smith and others 2009b). Global stressors are ubiquitous in nature and interact both directly and indirectly with regional or local stressors. Regional/local stressors in southern Nevada include: population growth and urbanization and associated increases in nitrogen deposition, energy development, water development, and recreation; increased effects of insects and disease; ongoing effects of livestock, wild horse and burro grazing; new and expanding invasive species; and altered fire regimes. This chapter provides background information on the stressors affecting southern Nevada's ecosystems that is needed to address Goal 1.0 in the SNAP Science Research Strategy, which is to restore, sustain, and enhance southern Nevada's ecosystems (Turner and others 2009). Human population growth and changes in land use strongly affect the type and magnitude of local/regional stressors. From 1960 to 2010, Nevada's growth rate was the highest in the nation (www.census.gov/prod/cen2010/briefs/c2010br-01.pdf). Clark County has experienced particularly high growth, with a population increase of greater than 40 percent since the 2000 census. Factors like land ownership, historic and current land use, proximity to human and energy developments, and desirability for recreation all influence the level of human-caused stress. The strong elevation/climate gradients and large difference in the environmental characteristics of southern Nevada ecosystems (fig. 1.2; Chapter 1) have a major influence on both patterns of land use and the dominant stressors for different ecosystem types. Shifts in land use related to population growth, urbanization, and energy development and largely focused in lower elevation ecosystems including sagebursh, blackbrush and shadscale, and Mojave Desert scrub. Water divisions influence riparian/aquatic ecosystems and springs, while groundwater pumping also has the potential to affect ecosystems that characterize lower valleys including Mojave Desert scrub. Recreational uses influence all ecosystems, and wild horse and burro use and livestock grazing affect all but alpine and subalpine ecosystems. Insects and disease, as well as invasive species are widespread stressors. Fire is limited to ecosystems with sufficient fuels to carry fire and is strongly influence by invasive species in lower elevation Mojave Desert scrub, blackbrush and shadscale, and sagebursh ecosystems. This chapter address aspects of several of the Goals and Sub-goals listed in the SNAP Science Research Strategy (table 1.3; Turner and others 2009). Altered fire regimes, invasive species, land use practices, and management actions are addressed in Goal 1 -- Sustain, Restore, and Enhance Southern Nevada's Ecosystems. The effects of these stressors on sensitive species and habitat are specifically addressed in Sub-goal 1.4 -- Sustain and Enhance Southern Nevada's Biotic Communities, to Preserve Biodiversity and Maintain Populations. Anthropogenic factors, such a recreation and urbanization, are referred to in Goal 2-- Provide for Responsible Use of Southern Nevada;s Lands in a Manner that Preserve Heritage Resources and Promotes an Understanding of Human Interaction with the Landscape.

Nevada↗
USGS1991

The intensities and magnitudes of volcanic eruptions

Ever since 1935, when C.F Richter devised the earthquake magnitude scale that bears his name, seismologists have been able to view energy release from earthquakes in a systematic and quantitative manner. The benefits have been obvious in terms of assessing seismic gaps and the spatial and temporal trends of earthquake energy release. A similar quantitative treatment of volcanic activity is of course equally desirable, both for gaining a further understanding of the physical principles of volcanic eruptions and for volcanic-hazard assessment. A systematic volcanologic data base would be of great value in evaluating such features as volcanic gaps, and regional and temporal trends in energy release.

Earthquakes & Volcanoes (USGS)↗
USGS2011

Chapter 10: Occurrence of non-native invasive plants: The role of anthropogenic features

The invasion of non-native plants in the Wyoming Basins Ecoregional Assessment (WBEA) area is a major economic and ecological stress, with invasions thought to be hastened by energy developments. Given the potential impacts of nonnative invasive plants and the rapid changes in land use in the WBEA, broad-scale assessments and predictive models of nonnative invasive plant distribution are needed. Using this information, the current extent of populations for targeting treatment and monitoring can be identified, the habitat affinities for forecasting where weeds may establish next determined, and the responses to individual human disturbances (such as energy developments) predicted. To address these needs, we conducted vegetation surveys across the WBEA area at 317 individual survey blocks (five plots per survey block) during the summers of 2005 and 2006. Survey blocks were stratified by both human disturbance and habitat productivity; in each of five plots per survey block the occurrence of 23 common nonnative invasive plants was recorded during early and late season surveys. Here, we report on the four most common invasive plants, crested wheatgrass ( Agropyron cristatum ), cheatgrass ( Bromus tectorum ), halogeton ( Halogeton glomeratus ), and Russian thistle ( Salsola spp. ). Occurrence models were generated for each species using random-effects logistic regression to account for nesting of plots within sample sites. Predictors of occupancy included local habitat, abiotic condition, and distance to anthropogenic features. Although occurrences of all four invasive plants were affected by habitat, abiotic, and anthropogenic factors, cheatgrass and Russian thistle were most strongly associated with anthropogenic disturbance, primarily major roads and energy well sites. We assessed relationships between environmental and anthropogenic predictors and species occurrences to identify the major factors affecting current species distribution, examined shape of the response in occurrence in relation to proximity to individual anthropogenic disturbances, and provided spatial predictions of the locations where invasive plants are most likely to occur.

Wyoming↗
USGS2000

Response of geese to aircraft disturbances

Low-flying aircraft can affect behavior, physiology, and distribution of wildlife (Manci et al., 1988), and over time, may impact a population by reducing survival and reproductive performance. Thus, it is important to identify the particular aspects of overflights that affect animals so that management strategies can be developed to minimize adverse effects. Waterfowl are particularly sensitive to low-flying aircraft (Manci et al., 1988) and respond at all stages of their annual cycle, including breeding (Gollop et al., 1974a; Laing, 1991), molting (Derksen et al., 1979; Mosbech and Glahder, 1991), migration (Jones and Jones, 1966; Belanger and Bedard, 1989), and wintering (Owens, 1977; Kramer et al., 1979; Henry, 1980). Waterfowl response can be quite variable both within and among species (Fleming et al., 1996). For example, response can vary with age, sex, and body condition of individual, habitat type and quality, and previous exposure to aircraft (Dahlgren and Korshgen, 1992). However, the most important factors influencing a response are aircraft type (Davis and Wiseley, 1974; Jensen, 1990), noise (Mosbech and Glahder, 1991; Temple, 1993), and proximity to the birds, as measured in altitude and lateral distance (Derksen et al., 1979; Belanger and Bedard, 1989; Ward et al., 1994). Wildlife managers can reduce impacts on a population by controlling or modifying these factors. In an experimental study conducted at Izembek Lagoon in southwestern Alaska in 1985-1988 (Ward and Stehn, 1989), we conducted planned aircraft overflights with control of aircraft type, noise, altitude, and lateral distance to flocks (hereafter called lateral distance) to measure behavioral response of fall-staging Pacific brant ( Branta bernicla nigricans ) and Canada geese ( B. canadensis taverneri ) to fixed- and rotary-wing aircraft. These data were then used to develop predictive models of the relationship between aircraft type, noise, altitude, and lateral distance and the response of geese (Ward et al., 1989). We also developed a simulation model incorporating energy intake and daily energy costs to assess the long-term consequences of repeated overflights on the ability of brant to obtain sufficient energy reserves necessary for fall migration and over winter survival (Ward and Stehn, 1989).

Alaska↗
USGS1994

Response of staging brant to disturbance at Izembek Lagoon, Alaska

Human disturbance of migrating waterfowl concerns managers of wildlife populations and refuges. Human disturbance may reduce food intake through interruption of foraging bouts or by displacement from feeding areas (Madsen 1985, Belanger and Bedard 1989), and it may increase energy expenditure from additional time in flight (Korschgen et al., 1985). Reduced food intake and increased energy expenditure can affect the ability of waterfowl to acquire nutrient reserves for successful migration (Fredrickson and Drobney 1979, Davis and Wiseley 1974, Belanger and Bedard 1990). Furthermore, nutrient reserves acquired during fall migration may influence overwinter survival (Haramis et al. 1986). Over 90% of the Pacific Flyway population of brant (Branta bernicla nigricans) annually migrates to the Izembek Lagoon, Alaska and adjacent areas in fall (Bellrose 1976, Reed et al. 1989). During the 4- to 10-week staging period, brant feed predominantly on energy-rich common eelgrass ( Zostera marina ) prior to a transoceanic flight to coastal wintering areas in Washington, Oregon, California, and Mexico (Hansen and Nelson 1957, Morehouse 1974, Bellrose 1976). The lzembek Lagoon, a wetland of international importance (Smart 1987), also is a major staging area for Canada geese ( Branta canadensis taverneri ), emperor geese ( Chen canagica ), and other waterbirds (Ward and Stehn 1989). Brant are disturbed by aircraft and other human activities. Jones and Jones (1966) noted that aircraft caused brant to take flight in fall at the Izembek Lagoon. Aircraft influence movements of molting brant and evoke escape responses (Derksen et al. 1979, Jensen 1990). Aircraft, boats, and hunters affect distribution of wintering brant and cause premature departures from feeding areas (Owens 1977, Kramer et al 1979, Henry 1980). However, few data have been published concerning the extent to which disturbance affects behavior of fall-staging brant. Our objective was to measure current disturbance levels and to determine the extent to which disturbance affects the behavior of brant at the Izembek Lagoon during fall. This baseline information is needed to monitor any future changes in these levels and to provide guidelines for alleviating conflicts where increased human activities cause excessive disturbance.

Alaska↗
USGS2000

Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska

Distinct sand lance populations occur within the relatively small geographic area of Lower Cook Inlet, Alaska. Marked meso-scale differences in abundance, growth, and mortality exist as a consequence of differing oceanographic regimes. Growth rate within populations (between years) was positively correlated with temperature. However, this did not extend to inter-population comparisons where differing growth rates were better correlated to marine productivity. Most sand lance reached maturity in their second year. Field observations and indices of maturity, gonad development, and ova-size distribution all indicated that sand lance spawn once each year. Sand lance spawned intertidally in late September and October on fine gravel/sandy beaches. Embryos developed over 67 days through periods of intertidal exposure and sub-freezing air temperatures. Mean dry-weight energy value of sand lance cycles seasonally, peaking in spring and early summer (20.91 kJg -1 for males, 21.08 kJg -1 for females), and subsequently declining by about 25% during late summer and fall (15.91 kJg -1 for males, 15.74 kJg -1 for females). Sand lance enter the winter with close to their minimum whole body energy content. Dry weight energy densities of juveniles increased from a minimum 16.67 kJg -1 to a maximum of 19.68 kJg -1 and are higher than adults in late summer.

Alaska↗
USGS2015

Wintering movements and habitat use of Surf Scoter (Melanitta perspicillata) in the mid-Atlantic U.S.

Wintering habitat use and migratory pathways are key issues facing sea ducks in the mid-Atlantic U.S. and elsewhere due to the potential for offshore wind energy development. A comprehensive understanding of important winter habitats and environmental characteristics determining sea duck abundance and distribution is paramount in advising marine spatial planning efforts in the region and identifying key resource areas for sea ducks. We captured and tracked 101 Surf Scoters to investigate the spatial patterns, temporal patterns, and environmental variation in migration and winter habitat use through a combination of satellite telemetry data and remotely collected environmental covariate information. We found that Surf Scoters in core-use areas utilized shallow (<40 m) areas within 4.5 km from shore. Resource selection models suggest that other dynamic variables such as sea surface temperatures, productivity, and salinity (and selected interactions among them) may also be important in determining valuable scoter habitat. Migration chronology of birds tracked in this study suggests that Surf Scoters wintering and migrating throughout the mid-Atlantic region could encounter future offshore wind energy facilities between mid-October and early May. Our analyses indicate Surf Scoters tagged along near-shore areas of the mid-Atlantic have a minimal likelihood of overlapping with current Wind Energy Areas (WEAs) in the mid-Atlantic, though activities associated with construction within WEAs, such as installation of transmission lines or vessel traffic within nearshore areas, or possible development of wind farms closer to shore and outside currently designated WEAs, may have a higher likelihood of overlapping with wintering Surf Scoters in the mid-Atlantic.

Report↗
USGS2013

Constraints on behaviour of a mining‐induced earthquake inferred from laboratory rock mechanics experiments

On December 12, 2004, an earthquake of magnitude 2.2, located in the TauTona Gold Mine at a depth of about 3.65 km in the ancient Pretorius fault zone, was recorded by the in-mine borehole seismic network, yielding an excellent set of ground motion data recorded at hypocentral distances of several km. From these data, the seismic moment tensor, indicating mostly normal faulting with a small implosive component, and the radiated energy were measured; the deviatoric component of the moment tensor was estimated to be M0 = 2.3×1012 N·m and the radiated energy ER = 5.4×108 J. This event caused extensive damage along tunnels within the Pretorius fault zone. What rendered this earthquake of particular interest was the underground investigation of the complex pattern of exposed rupture surfaces combined with laboratory testing of rock samples retrieved from the ancient fault zone (Heesakkers et al.2011a, 2011b). Event 12/12 2004 was the result of fault slip across at least four nonparallel fault surfaces; 25 mm of slip was measured at one location on the rupture segment that is most parallel with a fault plane inferred from the seismic moment tensor, suggesting that this segment accounted for much of the total seismic deformation. By applying a recently developed technique based on biaxial stick-slip friction experiments (McGarr2012, 2013) to the seismic results, together with the 25 mm slip observed underground, we estimated a maximum slip rate of at least 6.6 m/s, which is consistent with the observed damage to tunnels in the rupture zone. Similarly, the stress drop and apparent stress were found to be correspondingly high at 21.9 MPa and 6.6 MPa, respectively. The ambient state of stress, measured at the approximate depth of the earthquake but away from the influence of mining, in conjunction with laboratory measurements of the strength of the fault zone cataclasites, indicates that during rupture of the M 2.2 event, the normal stress acting on the large-slip fault segment was about 260 MPa, the yield stress was 172 MPa and the seismic efficiency was 0.05. Thus, for event 12/12 2004, 5% of the energy released by the earthquake was radiated and the remaining 95% was consumed in overcoming fault friction and expanding the zone of rupture.

Conference Paper↗
USGS2019

Hawaiian hoary bat (Lasiurus cinereus semotus) activity, diet and prey availability at the Waihou Mitigation Area, Maui

Habitat use, diet, prey availability, and foraging ecology of the endangered Hawaiian hoary bat (Lasiurus cinereus semotus, Vespertilionidae), was examined in the east Maui region inclusive of the Waihou Mitigation Area, Pu‘u Makua Restoration Area and the wind energy facility operated by Auwahi Wind Energy, LLC. The study was conducted to inform the mitigation and management requirements of Auwahi Wind Energy. Acoustic monitoring over the three-year period demonstrated that bats are present and actively forage year-round at the Waihou Mitigation Area. Over an 8-month span, 11 bats were uniquely color-banded and released, 3 of which were pregnant or lactating females, and highlights the importance of the area to breeding residents. Our study included the first genetic analysis of Hawaiian hoary bat diet, and confirms the inclusion of Coleoptera, Lepidoptera, Diptera, Hemiptera, and Blattodea among the prey items of this bat identified in previous microscopy-based studies. Hawaiian hoary bats consumed both native and non-native insect species, including several invasive species damaging to crop agriculture. Moths were the primary dietary component, both in prevalence among individual bats and the proportion of gene sequence counts. Through genetic analysis, we identified 18 Lepidoptera families (dominated by Noctuidae, Geometridae, Crambidae, Oecophoridae and Tortricidae) including 24 genus- or species-level taxa. Lepidoptera collected as caterpillars directly from vegetation did not appear in the diet of the 8 bat guano samples at the genus or species level. However, the occurrence of moth larva on native plants suggests that reforestation that includes host plants for these insect families may provide food for locally foraging bats.

Hawaii↗