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At least 1,441 records · Page 80Linked to original sources
USGS2011

Geologic map of the Ganiki Planitia quadrangle (V-14), Venus

The Ganiki Planitia (V-14) quadrangle on Venus, which extends from 25° N. to 50° N. and from 180° E. to 210° E., derives its name from the extensive suite of plains that dominates the geology of the northern part of the region. With a surface area of nearly 6.5 x 10 6 km 2 (roughly two-thirds that of the United States), the quadrangle is located northwest of the Beta-Atla-Themis volcanic zone and southeast of the Atalanta Planitia lowlands, areas proposed to be the result of large scale mantle upwelling and downwelling, respectively. The region immediately south of Ganiki Planitia is dominated by Atla Regio, a major volcanic rise beneath which localized upwelling appears to be ongoing, whereas the area just to the north is dominated by the orderly system of north-trending deformation belts that characterize Vinmara Planitia. The Ganiki Planitia quadrangle thus lies at the intersection between several physiographic regions where extensive mantle flow-induced tectonic and volcanic processes are thought to have occurred. The geology of the V-14 quadrangle is characterized by a complex array of volcanic, tectonic, and impact-derived features. There are eleven impact craters with diameters from 4 to 64 km, as well as four diffuse 'splotch' features interpreted to be the product of near-surface bolide explosions. Tectonic activity has produced heavily deformed tesserae, belts of complex deformation and rifts as well as a distributed system of fractures and wrinkle ridges. Volcanic activity has produced extensive regional plains deposits, and in the northwest corner of the quadrangle these plains host the initial (or terminal) 700 km of the Baltis Vallis canali, an enigmatic volcanic feature with a net length of ~7,000 km that is the longest channel on Venus. Major volcanic centers in V-14 include eight large volcanoes and eight coronae; all but one of these sixteen features was noted during a previous global survey. The V-14 quadrangle contains an abundance of minor volcanic features including individual shield volcanoes and localized fissure eruptions as well as many small annular structures and domes, which often serve as the source for local lava flows. The topographic and geophysical characteristics of the Ganiki Planitia quadrangle are less complex than the surface geology, but they yield equally valuable information about the region’s formation and evolution. Referenced to the mean planetary radius of 6051.84 km, the average elevation in the quadrangle is -0.26±0.86 km (2σ) with a full range of -2.58 km to 1.85 km. The highest 2.5 percent of elevations in the quadrangle (above 0.60 km) are associated primarily with the major tessera blocks and the peaks of a few volcanic edifices, whereas the lowest 2.5 percent (below -1.12 km) mostly occur within corona interiors and in the northwest corner of the quadrangle where the plains begin to merge into the Atalanta Planitia lowlands. At the ~4.6 km/pixel scale of the topography data, the mean point-to-point topographic slope is 0.63° and topographic slopes greater than 2° cover less than 5 percent of the region. Overall, the topography of the Ganiki Planitia quadrangle can be characterized as flat, low lying, and nearly devoid of abrupt topographic variation. Complementing this gentle topography, the geoid anomaly has a generally linear gradient that decreases north-northwest from a high of ~20 m at the southern edge of the quadrangle (the northern border of the Atla Regio anomaly) to a low of -30 to -40 m along the northern edge (Konopliv and others, 1999). The vertical component of the gravity anomaly varies from ~50 mGal to -40 mGal, and integrated analysis of the gravity and topography data indicates that dynamically supported regions and areas of thickened crust are both present within the quadrangle. Because the Ganiki Planitia quadrangle is a plains-dominated lowland area that lies between several major physiographic provinces (namely, Atla Regio, Atalanta Planitia, and Vinmara Planitia), a geologic map of the region may yield insight into a wide array of important problems in Venusian geology. The current mapping effort and analysis complements previous efforts to characterize aspects of the region’s geology, for example stratigraphy near parabolic halo crater sites, volcanic plains emplacement, wrinkle ridges, volcanic feature distribution, volcano deformation, coronae characteristics, lithospheric flexure, and various features along a 30±7.58° N. geotraverse. Our current research focuses on addressing four specific questions. Has the dominant style of volcanic expression within the quadrangle varied in a systematic fashion over time? Does the tectonic deformation within the quadrangle record significant regional patterns that vary spatially or temporally, and if so what are the scales, orientations and sources of the stress fields driving this deformation? If mantle upwelling and downwelling have played a significant role in the formation of Atla Regio and Atalanta Planitia as has been proposed, does the geology of Ganiki Planitia record evidence of northwest-directed lateral mantle flow connecting the two sites? Finally, can integration of the tectonic and volcanic histories preserved within the quadrangle help constrain competing resurfacing models for Venus?

Scientific Investigations Map↗
USGS2013

Natural-color and color-infrared image mosaics of the Colorado River corridor in Arizona derived from the May 2009 airborne image collection

The Grand Canyon Monitoring and Research Center (GCMRC) of the U.S. Geological Survey (USGS) periodically collects airborne image data for the Colorado River corridor within Arizona (fig. 1) to allow scientists to study the impacts of Glen Canyon Dam water release on the corridor’s natural and cultural resources. These data are collected from just above Glen Canyon Dam (in Lake Powell) down to the entrance of Lake Mead, for a total distance of 450 kilometers (km) and within a 500-meter (m) swath centered on the river’s mainstem and its seven main tributaries (fig. 1). The most recent airborne data collection in 2009 acquired image data in four wavelength bands (blue, green, red, and near infrared) at a spatial resolution of 20 centimeters (cm). The image collection used the latest model of the Leica ADS40 airborne digital sensor (the SH52), which uses a single optic for all four bands and collects and stores band radiance in 12-bits. Davis (2012) reported on the performance of the SH52 sensor and on the processing steps required to produce the nearly flawless four-band image mosaic (sectioned into map tiles) for the river corridor. The final image mosaic has a total of only 3 km of surface defects in addition to some areas of cloud shadow because of persistent inclement weather during data collection. The 2009 four-band image mosaic is perhaps the best image dataset that exists for the entire Arizona part of the Colorado River. Some analyses of these image mosaics do not require the full 12-bit dynamic range or all four bands of the calibrated image database, in which atmospheric scattering (or haze) had not been removed from the four bands. To provide scientists and the general public with image products that are more useful for visual interpretation, the 12-bit image data were converted to 8-bit natural-color and color-infrared images, which also removed atmospheric scattering within each wavelength-band image. The conversion required an evaluation of the histograms of each band’s digital-number population within each map tile throughout the corridor and the determination of the digital numbers corresponding to the lower and upper one percent of the picture-element population within each map tile. Visual examination of the image tiles that were given a 1-percent stretch (whereby the lower 1- percent 12-bit digital number is assigned an 8-bit value of zero and the upper 1-percent 12-bit digital number is assigned an 8-bit value of 255) indicated that this stretch sufficiently removed atmospheric scattering, which provided improved image clarity and true natural colors for all surface materials. The lower and upper 1-percent, 12-bit digital numbers for each wavelength-band image in the image tiles exhibit erratic variations along the river corridor; the variations exhibited similar trends in both the lower and upper 1-percent digital numbers for all four wavelength-band images (figs. 2–5). The erratic variations are attributed to (1) daily variations in atmospheric water-vapor content due to monsoonal storms, (2) variations in channel water color due to variable sediment input from tributaries, and (3) variations in the amount of topographic shadows within each image tile, in which reflectance is dominated by atmospheric scattering. To make the surface colors of the stretched, 8-bit images consistent among adjacent image tiles, it was necessary to average both the lower and upper 1-percent digital values for each wavelength-band image over 20 river miles to subdue the erratic variations. The average lower and upper 1-percent digital numbers for each image tile (figs. 2–5) were used to convert the 12-bit image values to 8-bit values and the resulting 8-bit four-band images were stored as natural-color (red, green, and blue wavelength bands) and color-infrared (near-infrared, red, and green wavelength bands) images in embedded geotiff format, which can be read and used by most geographic information system (GIS) and image-processing software. The tiff world files (tfw) are provided, even though they are generally not needed for most software to read an embedded geotiff image. All image data are projected in the State Plane (SP) map projection using the central Arizona zone (202) and the North American Datum of 1983 (NAD83). The map-tile scheme used to segment the corridor image mosaic followed the standard USGS quarter-quadrangle (QQ) map borders, but the high resolution (20 cm) of the images required further quarter segmentation (QQQ) of the standard QQ tiles, where the image mosaic covered a large fraction of a QQ map tile (segmentation shown in (figure 6), where QQ_1 to QQ_4 shows the number convention used to designate a quarter of a QQ tile). To minimize the size of each image tile, each image or map tile was subset to only include that part of the tile that had image data. In addition, some QQQ image tiles within a QQ tile were combined when adjacent QQQ map tiles were small. Thus, some image tiles consist of combinations of QQQ map tiles, some consist of an entire QQ map tile, and some consist of two adjoining QQ map tiles. The final image tiles number 143, which is a large number of files to list on the Internet for both the natural-color and color-infrared images. Thus, the image tiles were placed in seven file folders based on the one-half-degree geographic boundaries within the study area (fig. 7). The map tiles in each file folder were compressed to minimize folder size for more efficient downloading. The file folders are sequentially referred to as zone 1 through zone 7, proceeding down river (fig. 7). The QQ designations of the image tiles contained within each folder or zone are shown on the index map for each respective zone (figs. 8–14).

Arizona↗
USGS2018

Evaluating potential distribution of high-risk aquatic invasive species in the water garden and aquarium trade at a global scale based on current established populations

Aquatic non‐native invasive species are commonly traded in the worldwide water garden and aquarium markets, and some of these species pose major threats to the economy, the environment, and human health. Understanding the potential suitable habitat for these species at a global scale and at regional scales can inform risk assessments and predict future potential establishment. Typically, global habitat suitability models are fit for freshwater species with only climate variables, which provides little information about suitable terrestrial conditions for aquatic species. Remotely sensed data including topography and land cover data have the potential to improve our understanding of suitable habitat for aquatic species. In this study, we fit species distribution models using five different model algorithms for three non‐native aquatic invasive species with bioclimatic, topographic, and remotely sensed covariates to evaluate potential suitable habitat beyond simple climate matches. The species examined included a frog (Xenopus laevis), toad (Bombina orientalis), and snail (Pomacea spp.). Using a unique modeling approach for each species including background point selection based on known established populations resulted in robust ensemble habitat suitability models. All models for all species had test area under the receiver operating characteristic curve values greater than 0.70 and percent correctly classified values greater than 0.65. Importantly, we employed multivariate environmental similarity surface maps to evaluate potential extrapolation beyond observed conditions when applying models globally. These global models provide necessary forecasts of where these aquatic invasive species have the potential for establishment outside their native range, a key component in risk analyses.

Risk Analysis↗
USGS2017

Active tectonics of the northern Mojave Desert: The 2017 Desert Symposium field trip road log

The 2017 Desert Symposium field trip will highlight recent work by the U.S. Geological Survey geologists and geophysicists, who have been mapping young sediment and geomorphology associated with active tectonic features in the least well-known part of the eastern California Shear Zone (ECSZ). This area, stretching from Barstow eastward in a giant arc to end near the Granite Mountains on the south and the Avawatz Mountains on the north (Fig. 1-1), encompasses the two major structural components of the ECSZ—east-striking sinistral faults and northwest-striking dextral faults—as well as reverseoblique and normal-oblique faults that are associated with topographic highs and sags, respectively. In addition, folds and stepovers (both restraining stepovers that form pop-up structures and releasing stepovers that create narrow basins) have been identified. The ECSZ is a segment in the ‘soft’ distributed deformation of the North American plate east of the San Andreas fault (Fig. 1-1), where it takes up approximately 20-25% of plate motion in a broad zone of right-lateral shear (Sauber et al., 1994) The ECSZ (sensu strictu) begins in the Joshua Tree area and passes north through the Mojave Desert, past the Owens Valley-to-Death Valley swath and northward, where it is termed the Walker Lane. It has been defined as the locus of active faulting (Dokka and Travis, 1990), but when the full history from about 10 Ma forward is considered, it lies in a broader zone of right shear that passes westward in the Mojave Desert to the San Andreas fault (Mojave strike-slip province of Miller and Yount, 2002) and passes eastward to the Nevada state line or beyond (Miller, this volume). We will visit several accessible highlights for newly studied faults, signs of young deformation, and packages of syntectonic sediments. These pieces of a complex active tectonic puzzle have yielded some answers to longstanding questions such as: How is fault slip transfer in this area accommodated between northwest-striking dextral faults and eaststriking sinistral faults? How is active deformation on the Ludlow fault transferred northward, presumably to connect to the southern Death Valley fault zone? When were faults in this area of the central Mojave Desert initiated? Are faults in this area more or less active than faults in the ECSZ to the west? What is the role of NNW-striking faults and when did they form? How has fault slip changed over time? Locations and fault names are provided in figure 1-2. Important turns and locations are identified with locations in the projection: UTM, zone 11; datum NAD 83: (578530 3917335).

California↗
USGS1999

Depositional history of the Fire Clay coal bed (Late Duckmantian), Eastern Kentucky, USA

More than 3800 coal thickness measurements, proximate analyses from 97 localities, and stratigraphic and sedimentological analyses from more than 300 outcrops and cores were used in conjunction with previously reported palynological and petrographic studies to map individual benches of the coal and document bench-scale variability in the Fire Clay (Hazard No. 4) coal bed across a 1860 km2 area of the Eastern Kentucky Coal Field. The bench architecture of the Fire Clay coal bed consists of uncommon leader benches, a persistent but variable lower bench, a widespread, and generally thick upper bench, and local, variable rider benches. Rheotrophic conditions are inferred for the leader benches and lower bench based on sedimentological associations, mixed palynomorph assemblages, locally common cannel coal layers, and generally high ash yields. The lower bench consistently exhibits vertical variability in petrography and palynology that reflects changing trophic conditions as topographic depressions infilled. Infilling also led to unconfined flooding and ultimately the drowning of the lower bench mire. The drowned mire was covered by an air-fall volcanic-ash deposit, which produced the characteristic flint clay parting. The extent and uniform thickness of the parting suggests that the ash layer was deposited in water on a relatively flat surface without a thick canopy or extensive standing vegetation across most of the study area. Ash deposits led to regional ponding and establishment of a second planar mire. Because the topography had become a broadly uniform, nutrient-rich surface, upper-bench peats became widespread with large areas of the mire distant to clastic sources. Vertical sections of thick (> 70 cm), low-ash yield, upper coal bench show a common palynomorph change from arborescent lycopod dominance upward to fern and densospore-producing, small lycopod dominance, inferred as a shift from planar to ombrotrophic mire phases. Domed mires appear to have been surrounded by wide areas of planar mires, where the coal was thinner (< 70 cm), higher in ash yield, and dominated by arborescent lycopods. Rectangular thickness trends suggest that syndepositional faulting influenced peat accumulation, and possibly the position of the domed mire phase. Faulting also influenced post-depositional clastic environments of deposition, resulting in sandstone channels with angular changes in orientation. Channels and lateral facies were locally draped by high-ash-yield rider coal benches, which sometimes merged with the upper coal bench. These arborescent-lycopod dominant rider coal benches were profoundly controlled by palcotopography, much like the leader coal benches. Each of the benches of coal documented here represent distinctly different mires that came together to form the Fire Clay coal bed, rather than a single mire periodically split by clastic influx. This is significant as each bench of the coal has its own characteristics, which contribute to the total coal characteristics. The large data set allows interpretation of both vertical and lateral limits to postulated domed phases in the upper coal bench, and to the delineation of subtle tectonic structures that allow for meaningful thickness projections beyond the limits of present mining.A study was conducted to analyze the depositional history of the Fire Clay coal bed in the eastern Kentucky coal field. The study involved over 3800 coal thickness measurements, proximate analyses from 97 localities, and stratigraphic and sedimentological analyses from more than 300 outcrops and cores in conjunction with previously reported palynological and petrographic studies to map individual benches of the coal and document bench-scale variability.

International Journal of Coal Geology↗
USGS1973

Geologic map of the Grimaldi quadrangle of the Moon

The Grimaldi quadrangle lies at the southwest margin of Oceanus Procellarum about 1,000 km east of Orientale, the youngest o f the lunar multi-ringed basins. The distal ends of the ejecta blanket surrounding the Orient al e basin partly covers the western third of the quadrangle. The relatively small, two-ring Grimaldi basin is in the northwest corner of the quadrangle, and the Humorum basin l ies about 750 km to the southeast. A vestigial multi-ring basin mostly engulfed by mare appears to control the distribution of terra and mare along the southwest margin of Oceanus Procellarum ; the craters Hansteen and Billy are on a northwe s t-trending topographic high which represents part of the ring system of this basin. Terra materials of distinctive texture, apparently unrelated to multi-ring basins and probably of volcanic origin, occupy the central parts of the quadrangle.

IMAP↗
USGS2001

Surface-water, water-quality, and ground-water assessment of the Municipio of Carolina, Puerto Rico, 1997-99

To meet the increasing need for a safe and adequate supply of water in the municipio of Carolina, an integrated surface-water, water-quality, and ground-water assessment of the area was conducted. The major results of this study and other important hydrologic and water-quality features were compiled in a Geographic Information System and are presented in two 1:30,000-scale map plates to facilitate interpretation and use of the diverse water-resources data. Because the supply of safe drinking water was a critical issue during recent dry periods, the surface-water assessment portion of this study focused on analysis of low-flow characteristics in local streams and rivers. Low-flow characteristics were evaluated for one continuous-record gaging station, based on graphical curve-fitting techniques and log-Pearson Type III frequency analysis. Estimates of low-flow characteristics for seven partial-record stations were generated using graphical-correlation techniques. Flow-duration characteristics were computed for the one continuous-record gaging station and were estimated for the partial-record stations using the relation curves developed from the low-flow study. Stream low-flow statistics document the general hydrology under current land and water use. Low-flow statistics may substantially change as a result of streamflow diversions for public supply, and an increase in ground-water development, waste-water discharges, and flood-control measures; the current analysis provides baseline information to evaluate these impacts and develop water budgets. A sanitary quality survey of streams utilized 29 sampling stations to evaluate the sanitary quality of about 87 miles of stream channels. River and stream samples were collected on two occasions during base-flow conditions and were analyzed for fecal coliform and fecal streptococcus. Bacteriological analyses indicate that a significant portion of the stream reaches within the municipio of Carolina may have fecal coliform concentrations above the water-quality goal established by the Puerto Rico Environmental Quality Board (Junta de Calidad Ambiental de Puerto Rico) for inland surface waters. Sources of fecal contamination may include: illegal discharge of sewage to storm-water drains, malfunctioning sanitary sewer ejectors, clogged and leaking sewage pipes, septic tank leakage, unfenced livestock, and runoff from livestock pens. Long-term fecal coliform data at two sampling stations, Quebrada Blasina in Carolina and the Rio Grande de Loiza, downstream from the town of Trujillo Alto, indicate that the sanitary quality of Quebrada Blasina is and has generally been poor for more than a decade. The sanitary quality of the Rio Grande de Loiza has generally been in compliance with the water-quality goal standard fecal coliform concentrations established in July 1990 by the Puerto Rico Environmental Quality Board. Geologic, topographic, soil, hydrogeologic, and streamflow data were used to divide the municipio of Carolina into five hydrogeologic terranes. This integrated database was then used to evaluate the ground-water potential of each hydrogeologic terrane. Analysis suggests that areas with slopes greater than 15 degrees have relatively low ground-water development potential. Fractures may be locally important in enhancing the water-bearing properties in the hydrogeologic terranes containing igneous rocks. Potentiometric-surface elevations recorded in piezometers installed in the coastal area during this study were used to define ground-water flow directions in the hydrogeologic terranes composed of coastal plain clastic and limestone units. The resultant potentiometric map indicates that the coastal plain aquifer and streams in the lowland parts of the municipio of Carolina are hydraulically connected. The potentiometric map also indicates that ground-water discharge to the Rio Grande de Loiza, downstream from highway PR-3, has been enhanced by dredging of the streambed for

Water-Resources Investigations Report↗
USGS2016

Active faulting on the Wallula fault zone within the Olympic-Wallowa lineament, Washington State, USA

The Wallula fault zone is an integral feature of the Olympic-Wallowa lineament, an ∼500-km-long topographic lineament oblique to the Cascadia plate boundary, extending from Vancouver Island, British Columbia, to Walla Walla, Washington. The structure and past earthquake activity of the Wallula fault zone are important because of nearby infrastructure, and also because the fault zone defines part of the Olympic-Wallowa lineament in south-central Washington and suggests that the Olympic-Wallowa lineament may have a structural origin. We used aeromagnetic and ground magnetic data to locate the trace of the Wallula fault zone in the subsurface and map a quarry exposure of the Wallula fault zone near Finley, Washington, to investigate past earthquakes along the fault. We mapped three main packages of rocks and unconsolidated sediments in an ∼10-m-high quarry exposure. Our mapping suggests at least three late Pleistocene earthquakes with surface rupture, and an episode of liquefaction in the Holocene along the Wallula fault zone. Faint striae on the master fault surface are subhorizontal and suggest reverse dextral oblique motion for these earthquakes, consistent with dextral offset on the Wallula fault zone inferred from offset aeromagnetic anomalies associated with ca. 8.5 Ma basalt dikes. Magnetic surveys show that the Wallula fault actually lies 350 m to the southwest of the trace shown on published maps, passes directly through deformed late Pleistocene or younger deposits exposed at Finley quarry, and extends uninterrupted over 120 km.

Washington↗
USGS2010

Ensemble habitat mapping of invasive plant species

Ensemble species distribution models combine the strengths of several species environmental matching models, while minimizing the weakness of any one model. Ensemble models may be particularly useful in risk analysis of recently arrived, harmful invasive species because species may not yet have spread to all suitable habitats, leaving species-environment relationships difficult to determine. We tested five individual models (logistic regression, boosted regression trees, random forest, multivariate adaptive regression splines (MARS), and maximum entropy model or Maxent) and ensemble modeling for selected nonnative plant species in Yellowstone and Grand Teton National Parks, Wyoming; Sequoia and Kings Canyon National Parks, California, and areas of interior Alaska. The models are based on field data provided by the park staffs, combined with topographic, climatic, and vegetation predictors derived from satellite data. For the four invasive plant species tested, ensemble models were the only models that ranked in the top three models for both field validation and test data. Ensemble models may be more robust than individual species-environment matching models for risk analysis. ?? 2010 Society for Risk Analysis.

Risk Analysis↗
USGS1973

Atlas of Mars, Phoenicis Lacus quadrangle, MC-17

This mosaic is made with computer enhanced Mariner 9 pictures, rectified and scaled to a Mercator projection. Computer processing was performed by the Image Processing Laboratory (IPL) of the Jet Propulsion Laboratory (JPL). Processing included contrast enhancement and high-pass filtering which accentuates topographic features while subduing albedo variations. Photographic reproductions of the images were generated from the IPL digital magnetic tapes and mosaicked by the U.S. Geological Survey. Horizontal controls were derived from spacecraft tracking data, which are based on astronomical definitions of the spin axis and system of longitudes in use during the Mariner 9 mission. The projection is based on a theoretical dynamical ellipticity of 1/192. The scale is based on an equatorial radius of 3393.4 km. Standard deviation in image placement is less than 5 km at map scale.

Open-File Report↗
USGS2007

Predicting wetland plant community responses to proposed water-level-regulation plans for Lake Ontario: GIS-based modeling

Integrated, GIS-based, wetland predictive models were constructed to assist in predicting the responses of wetland plant communities to proposed new water-level regulation plans for Lake Ontario. The modeling exercise consisted of four major components: 1) building individual site wetland geometric models; 2) constructing generalized wetland geometric models representing specific types of wetlands (rectangle model for drowned river mouth wetlands, half ring model for open embayment wetlands, half ellipse model for protected embayment wetlands, and ellipse model for barrier beach wetlands); 3) assigning wetland plant profiles to the generalized wetland geometric models that identify associations between past flooding / dewatering events and the regulated water-level changes of a proposed water-level-regulation plan; and 4) predicting relevant proportions of wetland plant communities and the time durations during which they would be affected under proposed regulation plans. Based on this conceptual foundation, the predictive models were constructed using bathymetric and topographic wetland models and technical procedures operating on the platform of ArcGIS. An example of the model processes and outputs for the drowned river mouth wetland model using a test regulation plan illustrates the four components and, when compared against other test regulation plans, provided results that met ecological expectations. The model results were also compared to independent data collected by photointerpretation. Although data collections were not directly comparable, the predicted extent of meadow marsh in years in which photographs were taken was significantly correlated with extent of mapped meadow marsh in all but barrier beach wetlands. The predictive model for wetland plant communities provided valuable input into International Joint Commission deliberations on new regulation plans and was also incorporated into faunal predictive models used for that purpose.

Journal of Great Lakes Research↗
USGS2016

Topobathymetric elevation model development using a new methodology: Coastal National Elevation Database

During the coming decades, coastlines will respond to widely predicted sea-level rise, storm surge, and coastalinundation flooding from disastrous events. Because physical processes in coastal environments are controlled by the geomorphology of over-the-land topography and underwater bathymetry, many applications of geospatial data in coastal environments require detailed knowledge of the near-shore topography and bathymetry. In this paper, an updated methodology used by the U.S. Geological Survey Coastal National Elevation Database (CoNED) Applications Project is presented for developing coastal topobathymetric elevation models (TBDEMs) from multiple topographic data sources with adjacent intertidal topobathymetric and offshore bathymetric sources to generate seamlessly integrated TBDEMs. This repeatable, updatable, and logically consistent methodology assimilates topographic data (land elevation) and bathymetry (water depth) into a seamless coastal elevation model. Within the overarching framework, vertical datum transformations are standardized in a workflow that interweaves spatially consistent interpolation (gridding) techniques with a land/water boundary mask delineation approach. Output gridded raster TBDEMs are stacked into a file storage system of mosaic datasets within an Esri ArcGIS geodatabase for efficient updating while maintaining current and updated spatially referenced metadata. Topobathymetric data provide a required seamless elevation product for several science application studies, such as shoreline delineation, coastal inundation mapping, sediment-transport, sea-level rise, storm surge models, and tsunami impact assessment. These detailed coastal elevation data are critical to depict regions prone to climate change impacts and are essential to planners and managers responsible for mitigating the associated risks and costs to both human communities and ecosystems. The CoNED methodology approach has been used to construct integrated TBDEM models in Mobile Bay, the northern Gulf of Mexico, San Francisco Bay, the Hurricane Sandy region, and southern California.

Journal of Coastal Research↗
USGS2009

Age, geochemical composition, and distribution of Oligocene ignimbrites in the northern Sierra Nevada, California: Implications for landscape morphology, elevation, and drainage divide geography of the Nevadaplano

To gain a better understanding of the topographic and landscape evolution of the Cenozoic Sierra Nevada and Basin and Range, we combine geochemical and isotopic age correlations with palaeoaltimetry data from widely distributed ignimbrites in the northern Sierra Nevada, California. A sequence of Oligocene rhyolitic ignimbrites is preserved across the modern crest of the range and into the western foothills. Using trace and rare earth element geochemical analyses of volcanic glass, these deposits have been correlated to ignimbrites described and isotopically dated in the Walker Lane fault zone and in central Nevada (Henry et al. , 2004, Geologic map of the Dogskin mountain quadrangle; Washoe County, Nevada; Faulds et al. , 2005, Geology, v. 33, p. 505–508). Ignimbrite deposits were sampled within the northern Sierra Nevada and western Nevada, and four distinct geochemical compositions were identified. The majority of samples from within the northern Sierra Nevada have compositions similar to the tuffs of Axehandle Canyon or Rattlesnake Canyon, both likely sourced from the same caldera complex in either the Clan Alpine Mountains or the Stillwater Range, or to the tuff of Campbell Creek, sourced from the Desatoya Mountains caldera. New 40 Ar/ 39 Ar age determinations from these samples of 31.2, 30.9, and 28.7 Ma, respectively, support these correlations. Based on an Oligocene palinspastic reconstruction of the region, our results show that ignimbrites travelled over 200 km from their source calderas across what is now the crest of the Sierra Nevada, and that during that time, no drainage divide existed between the ignimbrite source calderas in central Nevada and sample locations 200 km to the west. Palaeoaltimetry data from Sierra Nevada ignimbrites, based on the hydrogen isotopic composition of hydration water in glass, reflect the effect of a steep western slope on precipitation and indicate that the area had elevations similar to the present-day range. These combined results suggest that source calderas were likely located in a region of high elevation to the east of the Oligocene Sierra Nevada, which had a steep western slope that allowed for the large extent and broad distribution of the ignimbrites.

International Geology Review↗
USGS2003

Spatial variability of groundwater recharge and its effect on shallow groundwater quality in southern New Jersey

Point estimates of groundwater recharge at 48 sediment-coring locations vary substantially (−18.5–1840 cm yr −1 ) in a 930-km 2 area of southern New Jersey. Darcian estimates of steady, long-term recharge made at depth in the unsaturated zone were estimated using pedotransfer functions of soil texture and interpolated (mapped) with nonparametric methods to assess aquifer vulnerability in the area. The probability of exceeding the median recharge (29.1 cm yr −1 ) is low in the southwestern and northeastern portions of the study area and high in the eastern and southeastern portions. Estimated recharge is inversely related to measured percentage clay and positively related to the percentage of well-drained soils near wells. Spatial patterns of recharge estimates, exceedance probabilities, and clay content indicate that sediment texture controls recharge in the study area. Relations with land elevation and a topographic wetness index were statistically insignificant. Nitrate concentration and atrazine (6-chloro- N 2 -ethyl- N 4 -isopropyl-1,3,5-triazine-2,4-diamine) percentage detection in samples of shallow groundwater (typically <10 m) are higher for low recharge sites (≤29.1 cm yr −1 ) than for high recharge sites (>29.1 cm yr −1 ) in agricultural and urban areas. Differences between high and low recharge sites in these areas are highly significant for NO 3 concentration, but not for atrazine concentration.

New Jersey↗
USGS2008

Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States

Spatial climate data sets of 1971–2000 mean monthly precipitation and minimum and maximum temperature were developed for the conterminous United States. These 30‐arcsec (∼800‐m) grids are the official spatial climate data sets of the U.S. Department of Agriculture. The PRISM (Parameter‐elevation Relationships on Independent Slopes Model) interpolation method was used to develop data sets that reflected, as closely as possible, the current state of knowledge of spatial climate patterns in the United States. PRISM calculates a climate–elevation regression for each digital elevation model (DEM) grid cell, and stations entering the regression are assigned weights based primarily on the physiographic similarity of the station to the grid cell. Factors considered are location, elevation, coastal proximity, topographic facet orientation, vertical atmospheric layer, topographic position, and orographic effectiveness of the terrain. Surface stations used in the analysis numbered nearly 13 000 for precipitation and 10 000 for temperature. Station data were spatially quality controlled, and short‐period‐of‐record averages adjusted to better reflect the 1971–2000 period. PRISM interpolation uncertainties were estimated with cross‐validation (C‐V) mean absolute error (MAE) and the 70% prediction interval of the climate–elevation regression function. The two measures were not well correlated at the point level, but were similar when averaged over large regions. The PRISM data set was compared with the WorldClim and Daymet spatial climate data sets. The comparison demonstrated that using a relatively dense station data set and the physiographically sensitive PRISM interpolation process resulted in substantially improved climate grids over those of WorldClim and Daymet. The improvement varied, however, depending on the complexity of the region. Mountainous and coastal areas of the western United States, characterized by sparse data coverage, large elevation gradients, rain shadows, inversions, cold air drainage, and coastal effects, showed the greatest improvement. The PRISM data set benefited from a peer review procedure that incorporated local knowledge and data into the development process.

International Journal of Climatology↗
USGS2016

High resolution mapping of development in the wildland-urban interface using object based image extraction

The wildland-urban interface (WUI), the area where human development encroaches on undeveloped land, is expanding throughout the western United States resulting in increased wildfire risk to homes and communities. Although census based mapping efforts have provided insights into the pattern of development and expansion of the WUI at regional and national scales, these approaches do not provide sufficient detail for fine-scale fire and emergency management planning, which requires maps of individual building locations. Although fine-scale maps of the WUI have been developed, they are often limited in their spatial extent, have unknown accuracies and biases, and are costly to update over time. In this paper we assess a semi-automated Object Based Image Analysis (OBIA) approach that utilizes 4-band multispectral National Aerial Image Program (NAIP) imagery for the detection of individual buildings within the WUI. We evaluate this approach by comparing the accuracy and overall quality of extracted buildings to a building footprint control dataset. In addition, we assessed the effects of buffer distance, topographic conditions, and building characteristics on the accuracy and quality of building extraction. The overall accuracy and quality of our approach was positively related to buffer distance, with accuracies ranging from 50 to 95% for buffer distances from 0 to 100 m. Our results also indicate that building detection was sensitive to building size, with smaller outbuildings (footprints less than 75 m 2 ) having detection rates below 80% and larger residential buildings having detection rates above 90%. These findings demonstrate that this approach can successfully identify buildings in the WUI in diverse landscapes while achieving high accuracies at buffer distances appropriate for most fire management applications while overcoming cost and time constraints associated with traditional approaches. This study is unique in that it evaluates the ability of an OBIA approach to extract highly detailed data on building locations in a WUI setting.

Colorado↗
USGS2014

Report of committee on glaciers, 1940–41

The personnel of the Committee is now as follows: Harry Fielding Reid, Professor Emeritus of Geology, Johns Hopkins University, 608 Cathedral Street, Baltimore, Maryland; William H. Hobbs, Professor Emeritus of Geology, University of Michigan, Ann Arbor, Michigan; Lawrence Martin, Chief of the Division of Maps, Library of Congress, Washington, D.C.; J. E. Church, Professor of Meteorology, Agricultural Experiment Station, University of Nevada, Reno, Nevada; Wm. Osgood Field, Jr., Explorer, 18 West Twelfth Street, New York, New York; Oliver Kehrlein, Chairman, Committee on Glacier Studies of Sierra Club, 1050 Mills Tower, 220 Bush Street, San Francisco, California; Kenneth N. Phillips, Associate Hydraulic Engineer, Water Resources Branch, United States Geological Survey, Chairman, Research Committee of the Mazamas, 606 Post‐Office Building, Portland, Oregon; William S. Cooper, Professor of Botany, University of Minnesota, Minneapolis, Minnesota; Gerald Fitzgerald, Senior Topographic Engineer, Alaska Branch, United States Geological Survey, Washington, D.C.; Laurence M. Gould, Professor of Geology, Carleton College, Northfield, Minnesota; Dr. Max Demorest, Department of Geology, Yale University, New Haven, Connecticut; François E. Matthes (Chairman), Senior Geologist, Section of Glacial Geology, United States Geological Survey, Washington, D.C.

Eos, Transactions, American Geophysical Union↗
USGS2013

Meeting the Science Needs of the Nation in the Wake of Hurricane Sandy-- A U.S. Geological Survey Science Plan for Support of Restoration and Recovery

n late October 2012, Hurricane Sandy came ashore during a spring high tide on the New Jersey coastline, delivering hurricane-force winds, storm tides exceeding 19 feet, driving rain, and plummeting temperatures. Hurricane Sandy resulted in 72 direct fatalities in the mid-Atlantic and northeastern United States, and widespread and substantial physical, environmental, ecological, social, and economic impacts estimated at near $50 billion. Before the landfall of Hurricane Sandy, the USGS provided forecasts of potential coastal change; collected oblique aerial photography of pre-storm coastal morphology; deployed storm-surge sensors, rapid-deployment streamgages, wave sensors, and barometric pressure sensors; conducted Light Detection And Ranging (lidar) aerial topographic surveys of coastal areas; and issued a landslide alert for landslide prone areas. During the storm, Tidal Telemetry Networks provided real-time water-level information along the coast. Long-term network and rapid-deployment real-time streamgages and water-quality monitors reported on river levels and changes in water quality. Immediately after the storm, the USGS serviced real-time instrumentation, retrieved data from over 140 storm-surge sensors, and collected other essential environmental data, including more than 830 high-water marks mapping the extent and elevation of the storm surge. Post-storm lidar surveys documented storm impacts to coastal barriers informing response and recovery and providing a new baseline to assess vulnerability of the reconfigured coast. The USGS Hazard Data Distribution System served storm related information from many agencies on the Internet on a daily basis. This science plan was developed immediately following Hurricane Sandy to coordinate continuing USGS activities with other agencies and to guide continued data collection and analysis to ensure support for recovery and restoration efforts. The data, information, and tools that are produced by implementing this plan will: (1) further characterize impacts and changes, (2) guide mitigation and restoration of impacted communities and ecosystems, (3) inform a redevelopment strategy aimed at developing resilient coastal communities and ecosystems, (4) improve preparedness and responsiveness to the next hurricane or similar coastal disaster, and (5) enable improved hazard assessment, response, and recovery for future storms along the hurricane prone shoreline of the United States. The activities outlined in this plan are organized in five themes based on impact types and information needs. These USGS science themes are: Theme 1: Coastal topography and bathymetry. Theme 2: Impacts to coastal beaches and barriers. Theme 3: Impacts of storm surge and estuarine and bay hydrology. Theme 4: Impacts on environmental quality and persisting contaminant exposures. Theme 5: Impacts to coastal ecosystems, habitats, and fish and wildlife. A major emphasis in the implementation of this plan will be on interacting with stakeholders to better understand their specific data and information needs, to define the best way to make information available, and to support applications of USGS science and expertise to decisionmaking.

Connecticut;Delaware;Maine;Maryl;Massachusetts;New↗