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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 199 records · Page 11Linked to original sources
USGS1996

Satellite imagery of the onset of streaming flow of ice streams C and D, West Antarctica

Five overlapping Landsat multispectral scanner satellite images of the interior of the West Antarctic ice sheet were enhanced with principal component analysis, high-pass filtering, and linear contrast stretching and merged into a mosaic by aligning surface features in the overlap areas. The mosaic was registered to geodetic coordinates, to an accuracy of about 1 km, using the five scene centers as control points. The onset of streaming flow of two tributaries of ice stream C and one tributary of ice stream D is visible in the mosaic. The onset appears to occur within a relatively short distance, less than the width of the ice stream, typically at a subglacial topographic feature, such as a step or ridge. The ice streams extend farther up into the interior than previously mapped. Ice stream D starts about 150 km from the ice divide, at an altitude of about 1500 m, approximately halfway up the convex-upward dome shape of the interior ice sheet. Ice stream D is relatively much longer than ice stream C, possibly because ice stream D is currently active, whereas ice stream C is currently inactive. The grounded portion of the West Antarctic ice sheet is perhaps best conceptualized as an ice sheet in which ice streams are embedded over most of its area, with slow-moving ice converging into fast-moving ice streams in a widely distributed pattern, much like that of streams and rivers in a hydrologic basin. A relic margin appears to parallel most of the south margin of the tributary of ice stream D, separated from the active shear margin by about 10 km or less for a distance of over 200 km. This means there is now evidence for recent changes having occurred in three of the five major ice streams which drain most of West Antarctica (B, C, and D), two of which (B and D) are currently active.

Journal of Geophysical Research C: Oceans↗
USGS1997

Resolution of fault slip along the 470-km-long rupture of the great 1906 San Francisco earthquake and its implications

Data from all available triangulation networks affected by the 1906 earthquake have been combined to assess the trade-off between slip resolution and its uncertainty and to construct a conservative image of coseismic slip along the rupture. Because of varying network aperture and station density, slip resolution is very uneven. Although slip is determined within uncertainties of ??1.0 m along 60% of the fault, constraints are poor on the remaining, mostly offshore portions of the rupture. Slip decreases from maxima of 8.6 and 7.5 m at Shelter Cove and Tomales Bay to 4.5 m near Mount Tamalpais and 2.7 m at Loma Prieta. The geodetically derived slip distribution is in poor agreement with estimates based on analysis of S wave seismograms, probably because these waves register only 20-30% of the total seismic moment obtained from longer-period surface waves. Consideration of a range of fault geometries for 1906 slip near Loma Prieta indicates right-lateral motions lie between 2.3 and 3.1 m. These values are considerably greater than the 1.5 m of measured surface slip on which several assessments of high earthquake hazard for this fault segment were based. This factor, along with the absence of 1989 slippage where 1906 surface slip was used to make the forecasts, casts doubt on some claims of success in predicting the 1989 M = 6.9 Loma Prieta earthquake.

Journal of Geophysical Research B: Solid Earth↗
USGS1998

Analysis of simulated advanced spaceborne thermal emission and reflection (ASTER) radiometer data of the Iron Hill, Colorado, study area for mapping lithologies

The advanced spaceborne thermal emission and reflection (ASTER) radiometer was designed to record reflected energy in nine channels with 15 or 30 m resolution, including stereoscopic images, and emitted energy in five channels with 90 m resolution from the NASA Earth Observing System AMI platform. A simulated ASTER data set was produced for the Iron Hill, Colorado, study area by resampling calibrated, registered airborne visible/infrared imaging spectrometer (AVIRIS) data, and thermal infrared multispectral scanner (TIMS) data to the appropriate spatial and spectral parameters. A digital elevation model was obtained to simulate ASTER-derived topographic data. The main lithologic units in the area are granitic rocks and felsite into which a carbonatite stock and associated alkalic igneous rocks were intruded; these rocks are locally covered by Jurassic sandstone, Tertiary rhyolitic tuff, and colluvial deposits. Several methods were evaluated for mapping the main lithologic units, including the unsupervised classification and spectral curve-matching techniques. In the five thermalinfrared (TIR) channels, comparison of the results of linear spectral unmixing and unsupervised classification with published geologic maps showed that the main lithologic units were mapped, but large areas with moderate to dense tree cover were not mapped in the TIR data. Compared to TIMS data, simulated ASTER data permitted slightly less discrimination in the mafic alkalic rock series, and carbonatite was not mapped in the TIMS nor in the simulated ASTER TIR data. In the nine visible and near-infrared channels, unsupervised classification did not yield useful results, but both the spectral linear unmixing and the matched filter techniques produced useful results, including mapping calcitic and dolomitic carbonatite exposures, travertine in hot spring deposits, kaolinite in argillized sandstone and tuff, and muscovite in sericitized granite and felsite, as well as commonly occurring illite/muscovite. However, the distinction made in AVIRIS data between calcite and dolomite was not consistently feasible in the simulated ASTER data. Comparison of the lithologie information produced by spectral analysis of the simulated ASTER data to a photogeologic interpretation of a simulated ASTER color image illustrates the high potential of spectral analysis of ASTER data to geologic interpretation.

Journal of Geophysical Research D: Atmospheres↗
USGS1998

Erosional valleys in the Thaumasia region of Mars: Hydrothermal and seismic origins

Analysis of erosional valleys, geologic materials and features, and topography through time in the Thaumasia region of Mars using co-registered digital spatial data sets reveals significant associations that relate to valley origin. Valleys tend to originate (1) on Noachian to Early Hesperian (stages 1 and 2) large volcanoes, (2) within 50–100 km of stages 1 and 2 rift systems, and (3) within 100 km of Noachian (stage 1) impact craters >50 km in diameter. These geologic preferences explain observations of higher valley-source densities (VSDs) in areas of higher elevations and regional slopes (>1°) because the volcanoes, rifts, and craters form high, steep topography or occur in terrain of high relief. Other stage 1 and stage 2 high, steep terrains, however, do not show high VSDs. The tendency for valleys to concentrate near geologic features and the overall low drainage densities in Thaumasia compared to terrestrial surfaces rule out widespread precipitation as a major factor in valley formation (as is proposed in wann, wet climate scenarios) except perhaps during the Early Noachian, for which much of the geologic record has been obliterated. Instead, volcanoes and rifts may indicate the presence of shallow crustal intrusions that could lead to local hydrothermal circulation, melting of ground ice and snow, and groundwater sapping. However, impact-crater melt would provide a heat source at the surface that might drive away water, fonning valleys in the process. Post-stage 1 craters mostly have low nearby VSDs, which, for valleys incised in older rocks, suggests burial by ejecta and, for younger valleys, may indicate desiccation of near-surface water and deepening of the cryosphere. Later Hesperian and Amazonian (stages 3 and 4) valleys originate within 100–200 km of three young, large impact craters and near rifts systems at Warrego Valles and the southern part of Coprates rise. These valleys likely developed when the cryosphere was a couple kilometers or more thick, inhibiting valley development by hydrothermal circulation. However, eruption of groundwater may have occurred from impact-induced fracturing and lateral and perhaps minor upward transport of water due to seismic pumping. The two smaller craters formed along the plateau margin where the highest potential hydraulic head would occur in aquifers beneath the plateau. In the case of the larger crater (Lowell, 200 km in diameter), potential aquifers would likely be at depths of kilometers below the cryosphere. Seismic energy generated by the Lowell impactor would have been much greater, pumping both groundwater and perhaps fluidized slurry to the surface from beneath the cryosphere to form the young valleys and flow deposit. Along the margin of Thaumasia, tectonic pressurization of groundwater also may have contributed to valley formation. Dissection of rim materials of the Argyre impact may relate to tectonic activity and the unconsolidated state of basin ejecta.

Journal of Geophysical Research E: Planets↗
USGS2012

Groundwater Recharge Conference Reading, England September 21-24, 1970

An international Conference on Artificial Groundwater Recharge was held at the University of Reading, Whiteknights Park, Reading, Berkshire, England, sponsored by the Water Research Association, Medmenham, Marlow, Buckinghamshire. One hundred sixty-one delegates, representing 20 countries, registered. Five excellent tours were made available for them, to such installations as: the Hydraulics Research Station and Institute of Hydrology, Weilingford, Berkshire; the Metropolitan Water Board, Ashford Common Works, Sunbury-on-Thames; the Water Pollution Research Laboratory, Stevenage; and the Water Research Association, Medmenham, and Water Resources Board, Reading, Berkshire.

Eos Science News↗
USGS2011

Geomagnetic Workshop

A workshop on geomagnetism, sponsored by the Geologic Division of the U.S. Geological Survey, was held in the Denver West Office Complex in Golden, Colorado, April 13–15, 1982. There were 90 registered participants from government agencies, academic institutions, and industry. This effort stemmed from the realization that geomagnetism, once a small but coherent discipline, has now expanded into numerous areas of the geosciences, yet those doing research in these specialties seldom make contact outside their area of immediate interest. The impetus for this event came from the members of a committee formed to review the geomagnetic activities within the U.S. Geological Survey. They observed that the level of communication between the various elements of this now diverse discipline was inadequate, not only within their organization but also between federal agencies, academia, and the private sector. While the desire was to cover as much of geomagnetism as possible, it was necessary for a workshop of reasonable size and length to exclude some important areas of the subject: magnetic reversal chronology, studies of the externally produced variations, and most aspects of internal induction. The plan was to give emphasis to some of the newer areas: those which have recently seen a high level of activity and those with increasing activity abroad compared to that in the United States. The purpose was to evaluate the status and problems in selected areas with an eye to those whose emphasis might produce fruitful results in the next decade.

Eos, Transactions, American Geophysical Union↗
USGS2010

The Goodman swell: A lithospheric flexure caused by crustal loading along the midcontinent rift system

Rb-Sr biotite ages of Archean and Early to Middle Proterozoic crystalline rocks in northern Wisconsin and adjacent Upper Peninsula of Michigan describe a regionally systematic pattern related to differential uplift. An “age low” occurs in northern Wisconsin where values range from 1070–1172 Ma for rocks with crystallization ages of 1760 to 1865 Ma. These values overlap with the main episode of mafic igneous activity (1090 to 1120 Ma) along the Midcontinent rift system (MRS). We interpret these low biotite ages as registering closure due to cooling below the 300°C isotherm as a consequence of uplift and rapid erosion of an area that we are informally naming the Goodman swell. The position of the Goodman swell is independent of the Archean and Early Proterozoic regional geologic framework but closely linked with the curvilinear (concave to the south) MRS. We interpret the swell to be a forebulge imposed on an elastic crust by loading of mafic igneous rocks along and within the axis of the MRS. The southward concavity of load axes resulted in flexural interaction that localized the swell. Because of rapid uplift the swell may have been a source area for clastic sediments in the rift sequence.

Lake Superior↗
USGS2014

Montana earthquakes noted in pennsylvania mine‐water pools

A recent paper by daCosta [1959] reported water ‐level fluctuations caused by the Montana earthquake of August 18, 1959, and mentioned the fluctuations registered in three mine ‐ water pools of the Northern anthracite field in northeastern Pennsylvania , ten miles north of Wilkes‐Barre. This paper will discuss the water ‐level phenomena of these pools in more detail. Most of the coal mines near Wilkes‐Barre are idle, and ground water is forming extensive mine ‐ water pools in the underground mine openings. Some of the pools are interconnected by boreholes, tunnels, and other openings through the barrier pillars between adjacent mines.

Montana↗
USGS2022

Wildfire imagery reduces risk information-seeking among homeowners as property wildfire risk increases

Negative imagery of destruction may induce or inhibit action to reduce risks from climate-exacerbated hazards, such as wildfires. This has generated conflicting assumptions among experts who communicate with homeowners: half of surveyed wildfire practitioners perceive a lack of expert agreement about the effect of negative imagery (a burning house) on homeowner behavior, yet most believe negative imagery is more engaging. We tested whether this expectation matched homeowner response in the United States. In an online experiment, homeowners who viewed negative imagery reported more negative emotions but the same behavioral intentions compared to those who viewed status-quo landscape photos. In a pre-registered field experiment, homeowners who received a postcard showing negative imagery were equally likely, overall, to visit a wildfire risk webpage as those whose postcard showed a status quo photo. However, the negative imagery decreased webpage visits as homeowners’ wildfire risk increased. These results illustrate the importance of testing assumptions to encourage behavioral adaptation to climate change.

Communications Earth & Environment↗
USGS2025

A psychologically wise intervention to inform relational organizing in the face of climate and ocean change

Widespread climate action is broadly recognized as necessary to reduce climate change impacts on oceans (“ocean change”), but threats to ocean ecosystems are commonly perceived as distant, irrelevant, and unchangeable. Communicating about ocean change, therefore, requires message framing strategies targeting evidence-based psychological precursors to behavior. In a pre-registered case study of coastal visitors in Oregon, United States ( n = 2414), we tested the influence of psychologically wise message about ocean change on climate action intentions. We primarily focused on influencing relational organizing: people’s willingness to encourage others to act. A behavior-specific message targeting relational organizing efficacy beliefs significantly but weakly increased intentions for relational organizing regarding ocean change compared to a control. Neither a connectedness to coast (place-based) message nor an ocean acidification (proximate threat-based) message had detectable effects on intentions. Our results suggest that targeting relational organizing efficacy may increase climate action intentions for the protection of coastal ecosystems.

npj Ocean Sustainability↗
USGS2021

Emerging investigator series: Municipal wastewater as a year-round point source of neonicotinoid insecticides that persist in an effluent-dominated stream

Neonicotinoids in aquatic systems have been predominantly associated with agriculture, but some are increasingly being linked to municipal wastewater. Thus, the aim of this work was to understand the municipal wastewater contribution to neonicotinoids in a representative, characterized effluent-dominated temperate-region stream. Our approach was to quantify the spatiotemporal concentrations of imidacloprid, clothianidin, thiamethoxam, and transformation product imidacloprid urea: 0.1 km upstream, the municipal wastewater effluent, and 0.1 and 5.1 km downstream from the wastewater outfall (collected twice-monthly for one year under baseflow conditions). Quantified results demonstrated that wastewater effluent was a point-source of imidacloprid (consistently) and clothianidin (episodically), where chronic invertebrate exposure benchmarks were exceeded for imidacloprid (36/52 samples; 3/52 > acute exposure benchmark) and clothianidin (8/52 samples). Neonicotinoids persisted downstream where mass loads were not significantly different than those in the effluent. The combined analysis of neonicotinoid effluent concentrations, instream seasonality, and registered uses in Iowa all indicate imidacloprid, and seasonally clothianidin, were driven by wastewater effluent, whereas thiamethoxam and imidacloprid urea were primarily from upstream non-point sources (or potential in-stream transformation for imidacloprid urea). This is the first study to quantify neonicotinoid persistence in an effluent-dominated stream throughout the year—implicating wastewater effluent as a point-source for imidacloprid (year-round) and clothianidin (seasonal). These findings suggest possible overlooked neonicotinoid indoor human exposure routes with subsequent implications for instream ecotoxicological exposure.

Environmental Sciences: Processes & Impacts↗
USGS2002

Population viability analysis of the Florida manatee ( Trichechus manatus latirostris ), 1976-1991

Recent development of age-determination techniques for Florida manatees (Trichechus manatus latirostris) has permitted derivation of age-specific data on reproduction and survival of a sample of 1212 carcasses obtained throughout Florida from 1976–1991. Population viability analysis using these data projects a slightly negative growth rate (−0.003) and an unacceptably low probability of persistence (0.44) over 1000 years. The main factors affecting population projections were adult survival and fecundity. A 10% increase in adult mortality would drive the population to extinction over a 1000-year time scale, whereas a 10% decrease in adult mortality would allow slow population growth. A 10% decrease in reproduction would also result in extinction. We conclude that management must focus on retaining and improving the conditions under which manatee demography operates. The major identified agent of mortality is boat-manatee collisions, and rapidly increasing numbers of humans and registered boats portend an increase in manatee mortality. Zoning of manatee-occupied waters for reductions in boating activity and speed is essential to safeguard the manatee population. If boating regulations being implemented by the state of Florida in each of 13 key coastal counties are completed, enforced, and effective, manatees and human recreation could coexist indefinitely. If regulation is unsuccessful, the Florida manatee population is likely to decline slowly toward extinction.

Conservation Biology↗
USGS2012

Lidar-Based Rock-Fall Hazard Characterization of Cliffs

Rock falls from cliffs and other steep slopes present numerous challenges for detailed geological characterization. In steep terrain, rock-fall source areas are both dangerous and difficult to access, severely limiting the ability to make detailed structural and volumetric measurements necessary for hazard assessment. Airborne and terrestrial lidar survey methods can provide high-resolution data needed for volumetric, structural, and deformation analyses of rock falls, potentially making these analyses straightforward and routine. However, specific methods to collect, process, and analyze lidar data of steep cliffs are needed to maximize analytical accuracy and efficiency. This paper presents observations showing how lidar data sets should be collected, filtered, registered, and georeferenced to tailor their use in rock fall characterization. Additional observations concerning surface model construction, volumetric calculations, and deformation analysis are also provided.

California↗
USGS1957

Measuring streamflow under ice conditions

Effects of ice formation on stage discharge relations; occurrence and effect of surface, frazil, and anchor ice is described and recorder graphs registering these effects are shown; one investigation of siphon action is detailed; factors affecting accuracy of ice-affected records.

Journal of the Hydraulics Division↗
USGS2018

Effectiveness of a fish ladder for two Neotropical migratory species in the Paraná River

We evaluated fish ladder effectiveness at Porto Primavera Dam in the Upper Paraná River, for two Neotropical migratory fish species. Overall, 564 fish (448 Megaleporinus obtusidens and 116 M. piavussu ) were PIT-tagged, released in upstream and downstream areas (on the left and right banks), and monitored continuously for 4 years. The fish performed two-way movements through the fish ladder, ascending from the tailrace and descending from the forebay. We registered 46 M. obtusidens (10.3%) and only 3 M. piavussu (2.6%) from the fish ladder, therefore all analyses were focused on M. obstusidens . Entry proportion ranged from 0 to 48.1% depending on release site and was greatest for fish released downstream near the fish ladder entrance. Entry times ranged from 3.0 to 384.0 days, and median times were 32.9 and 25.8 days for downstream and upstream, respectively. Of fish that entered the fish ladder, passage percentages were 80% for fish release downstream and 100% for fish released upstream, and median transit time was 0.7 and 0.9 hours, respectively. Results suggest that if guidance and entry conditions can be improved, this fish ladder design holds promise as an effective solution for providing passage in both directions.

Marine and Freshwater Research↗
USGS1992

Land cover mapping of the Upper Kuskokwim Resource Management Area, Alaska, using Landsat and a digital data base approach

Digital land cover and terrain data for the Upper Kuskokwim Resource Management Area in south-central Alaska were produced by the U.S. Geological Survey for the U.S. Bureau of Land Management. These and other environmental data were incorporated into a digital data base to assist in the production of a land cover map and to facilitate in the management and planning of the area. The digital data base is registered to a 50 m Universal Transverse Mercator grid and is stored on computer-compatible tape to facilitate transfer between different processing systems. The data base includes land cover classifications, terrain models (elevation, slope, aspect, solar illumination), autumn and winter Landsat multi-spectral scanner data, soils and surficial geology data, and area boundary. The spectral classification of Landsat multi-spectral scanner data resulted in seven major classes and 24 subclasses. Major classes were forest, shrubland, dwarf scrub, herbaceous, barren, water, and other.

Canadian Journal of Remote Sensing↗
USGS1992

Analyzing vegetation dynamics of land systems with satellite data

Large area assessment of vegetation conditions is a major requirement for understanding the impact of weather on food, fiber, and forage production. The distribution of vegetation is largely associated with climate, terrain characteristics, and human activity. The interpretation of vegetation dynamics from satellite data can be improved by stratifying the land surface into ecoregions. The Soil Conservation Service, U.S. Department of Agriculture, has developed a system for mapping major land resource areas (MLRA) that groups land areas in the United States on the basis of climate, physiography, land use, and land cover characteristics. In 1989, the U.S. Geological Survey used National Oceanic and Atmospheric Administration weather satellite data to conduct a biweekly assessment of vegetation conditions in 17 western states. Advanced Very High Resolution Radiometer data were acquired daily, and were geographically registered, and the normalized difference vegetation index (NDVI) was computed for the Western United States during the 1989 growing season. Fifteen biweekly NDVI data sets were used to evaluate MLRA's as an appropriate stratification for monitoring and interpreting vegetation conditions in the study area. The results demonstrate the feasibility of using MLRA's to stratify areas for monitoring phenological development and vegetation condition assessment within the growing season. Assessments of the NDVI at biweekly intervals are adequate for monitoring seasonal growth patterns on MLRA's where rangelands, forests, or cultivated agriculture are the primary resource type. Descriptive statistics are indicators of the uniformity or diversity of land use and land cover within an MLRA. Growing season profiles of the NDVI are characterized by the seasonal effects of climate on various land use and land cover classes.

Geocarto International↗
USGS2010

Characterizing 6 August 2007 Crandall Canyon mine collapse from ALOS PALSAR InSAR

We used ALOS InSAR images to study land surface deformation over the Crandall Canyon mine in Utah, which collapsed on 6 August 2007 and killed six miners. The collapse was registered as a ML 3.9 seismic event. An InSAR image spanning the time of the collapse shows 25–30 cm surface subsidence over the mine. We used distributed dislocation sources to model the deformation field, and found that a collapse source model alone does not adequately fit the deformation field. Normal faulting is also required, such that the event is best characterized as a ‘trapdoor’ collapse. The calculated moment of the normal fault is about the same as the moment of the collapse source, with each larger than the seismically computed moment. Our InSAR results, including the location of the event, the extent of the collapsed area, and constraints on the shearing component of the deformation source, all confirm and extend recent seismic studies of the 6 August 2007 event.

Utah↗