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At least 181 records · Page 10Linked to original sources
USGS2017

Paleozoic and mesozoic GIS data from the Geologic Atlas of the Rocky Mountain Region: Volume 1

The Rocky Mountain Association of Geologists (RMAG) is, once again, publishing portions of the 1972 Geologic Atlas of the Rocky Mountain Region (Mallory, ed., 1972) as a geospatial map and data package. Georeferenced tiff (Geo TIFF) images of map figures from this atlas has served as the basis for these data products. Shapefiles and file geodatabase features have been generated and cartographically represented for select pages from the following chapters: • Phanerozoic Rocks (page 56) • Cambrian System (page 63) • Ordovician System (pages 78 and 79) • Silurian System (pages 87 - 89) • Devonian System (pages 93, 94, and 96 - 98) • Mississippian System (pages 102 and 103) • Pennsylvanian System (pages 114 and 115) • Permian System (pages 146 and 149 - 154) • Triassic System (pages 168 and 169) • Jurassic System (pages 179 and 180) • Cretaceous System (pages 197 - 201, 207 - 210, 215, - 218, 221, 222, 224, 225, and 227). The primary purpose of this publication is to provide regional-scale, as well as local-scale, geospatial data of the Rocky Mountain Region for use in geoscience studies. An important aspect of this interactive map product is that it does not require extensive GIS experience or highly specialized software.

Book↗
USGS1965

Vigil Network sites: A sample of data for permanent filing

The Vigil Network consists of places where observations are made through time to record changes in landscape features over a long period. Resurveys will usually be made once each year or every few years and the period of observation, hopefully, will extend through and beyond the International Hydrological Decade. Vigil Network sites will usually be chosen to represent some typical feature of a given landscape. In the example shown here, the feature is a small ephemeral channel in a basin of moderate relief underlain by silty sandstone typical of the surrounding area. Vigil sites are not protected from man's influence and indeed may be selected because of the possible or portending cultural influences. In this respect they differ from the Bench Mark Network whose purpose is to make precise observations of hydrologic factors in areas uninfluenced by and protected from man's use. The factors which might be observed are many and varied. A few might be mentioned here, others are explained at length elsewhere (Miller and Leopold, 1963; Leopold, 1962). Streamchannel position, form, depth, and profile; vegetation in form of transects or quadrats; soil movement on slopes; rock movement on slopes or in channels. These and many more would yield valuable information on changes with time. To assure permanence of initial field observations, including reference points, bench marks, and cross sections, brief descriptions, maps, and initial data should be filed identically in designated repositories where the data will be made available for inspection by any interested scientist. It is recommended that the designation of two such locations where records of the type here attached will be filed be taken up by the Coordinating Council of the International Hydrological Decade. In designating such repositories it should be recognized that there is no need for elaborate indexing. The main requirement is merely the maintenance of a simple file where the data are stored and can be inspected or copied by any scientist. There need be no special provision for lending or reproduction services. The present document is an example showing what data, maps, and descriptions should be included in those permanent files at the two repositories. The material in these repositories should be sufficient to permit someone in the indefinite future to find and remeasure the same features described now. Thus the scientific value of the original surveys increases with time, - provided that the descriptions are sufficient to allow a person to find with assurance the original feature in the field. It must be visualized that a permanent repository must economize in space. Thus, as the example here shows, the filed material is not all of the original field notes but a summary, brief but descriptive.

International Association of Scientific Hydrology ↗
USGS1998

Remote sensing in the USGS Mineral Resource Surveys Program in the eastern United States

Mineral deposits commonly occur within special geologic units or structures, such as fault zones, which can be detected and mapped from aircraft and satellite images. Modern techniques analyze multispectral images that record the way solar energy is reflected or emitted by the materials exposed at the Earth's surface. In sparsely vegetated regions, including most of the Western United States, mineral composition is determined directly by analyzing the spectral properties of rock outcrops. In more densely vegetated terrain, such as the Eastern United States, rock and soil composition can be determined directly in manmade exposures, such as plowed fields and construction sites, or much more general determinations can be made indirectly by analyzing the distribution and apparent health of naturally occurring plants. The association of certain plants with particular rock or soil types has been known for decades. For example, coniferous trees grow preferentially on well-drained sandy soil, whereas deciduous trees dominate on shaly bedrock. These two forest types reflect solar radiation quite differently and, therefore, are distinguished readily in conventional aerial photographs. More subtle plant-bedrock associations require digital multispectral image analysis to infer compositional information from the spectral characteristics of the forest canopy.

Information Handout↗
USGS1975

Paleotectonic investigations of the Pennsylvanian system in the United States, Part II: Interpretive summary and special features of the Pennsylvanian system

Interpretation of the paleotectonic history of the Pennsylvanian System is represented on two sets of maps, one referred to as interpretive isopach maps and the other as interpretive paleotectonic maps (pi. 15A-C). Each set includes five maps, one for each interval of the Pennsylvanian. All maps of both sets were prepared at the same scale (1:5,000,000) and are published at a scale of 1:10,000,000. Therefore direct comparisons can readily be made.

Professional Paper↗
USGS2005

A comparative analysis of the Global Land Cover 2000 and MODIS land cover data sets

Accurate and up-to-date global land cover data sets are necessary for various global change research studies including climate change, biodiversity conservation, ecosystem assessment, and environmental modeling. In recent years, substantial advancement has been achieved in generating such data products. Yet, we are far from producing geospatially consistent high-quality data at an operational level. We compared the recently available Global Land Cover 2000 (GLC-2000) and MODerate resolution Imaging Spectrometer (MODIS) global land cover data to evaluate the similarities and differences in methodologies and results, and to identify areas of spatial agreement and disagreement. These two global land cover data sets were prepared using different data sources, classification systems, and methodologies, but using the same spatial resolution (i.e., 1 km) satellite data. Our analysis shows a general agreement at the class aggregate level except for savannas/shrublands, and wetlands. The disagreement, however, increases when comparing detailed land cover classes. Similarly, percent agreement between the two data sets was found to be highly variable among biomes. The identified areas of spatial agreement and disagreement will be useful for both data producers and users. Data producers may use the areas of spatial agreement for training area selection and pay special attention to areas of disagreement for further improvement in future land cover characterization and mapping. Users can conveniently use the findings in the areas of agreement, whereas users might need to verify the informaiton in the areas of disagreement with the help of secondary information. Learning from past experience and building on the existing infrastructure (e.g., regional networks), further research is necessary to (1) reduce ambiguity in land cover definitions, (2) increase availability of improved spatial, spectral, radiometric, and geometric resolution satellite data, and (3) develop advanced classification algorithms.

Remote Sensing of Environment↗
USGS2002

Implications for evaporite tectonism in the Carbondale and Eagle collapse centers of west-central Colorado, based on reprocessed seismic reflection data

Reprocessing of approximately 64 km of seismic reflection data along five seismic lines has led to new interpretations of evaporite tectonism associated with the Pennsylvanian Eagle Valley Evaporite of the central Colorado trough. Evidence of the oldest evaporite tectonism in the region, imaged by the seismic data, occurs in the Eagle collapse center at Hardscrabble Mountain. Here, the Triassic-Permian State Bridge Formation is abnormally thick, reflecting an outflow of underlying evaporite. On the west side of the Carbondale collapse center, structural wedging formed the west-dipping Grand Hogback monocline during early Tertiary Laramide deformation close to the western margin of the late Paleozoic central Colorado trough. Uplimb thrusts beneath the steep face of the monocline provide evidence of backthrusting. The presence of the Roaring Fork diapir proximal to the point of greatest curvature of the Grand Hogback monocline at the Leadville reflector level suggests that diapirism may have begun during formation of the monocline. Evidence for late Cenozoic evaporite tectonism is observed in all the seismic lines in spite of the difficulty of imaging shallow, young deposits that record evidence of abundant late Cenozoic evaporite tectonism observed during geologic mapping.

Colorado↗
USGS2010

Implications of geophysical analysis on basin geometry and fault offsets in the northern Colorado River extensional corridor and adjoining Lake Mead region, Nevada and Arizona

The northern Colorado River extensional corridor and Lake Mead region are characterized by prominent gravity and magnetic anomalies that provide insight into the geometry of extensional basins, amount of vertical and strike-slip offset on faults that bound these basins, and composition of major basement blocks. Although large-magnitude extension throughout the extensional corridor and major strike-slip faulting north of Lake Mead have highly disrupted many basins, most of the older basins (middle to late Miocene) are not associated with prominent geophysical anomalies. Instead, the most conspicuous anomalies (e.g., gravity lows) generally correspond to the younger (late Miocene to recent), structurally more coherent basins. Most of the geophysically expressed basins lie north of Lake Mead and are bounded by Quaternary normal and/or strike-slip fault zones. Both Quaternary faults and geophysically conspicuous basins are largely absent south of Lake Mead, where the only prominent gravity low corresponds to a structurally intact basin filled primarily with halite along the less extended, eastern margin of the corridor. Relatively continuous northeast-trending magnetic anomalies south of Lake Mead, presumably caused by Proterozoic basement rocks, suggest that strike-slip displacement is negligible on many of the major normal faults. In contrast, magnetic anomalies are smeared along the Lake Mead fault system and Las Vegas Valley shear zone. Offset anomalies suggest left-lateral displacement of 12–20 km for the Hamblin Bay fault zone, 12–15 km for the Lime Ridge fault, and 12 km on the Gold Butte fault. These values are compatible with or lower than published estimates based on geologic mapping.

Arizona, Nevada↗
USGS1972

Status of flood-plain mapping, greater Pittsburgh region, Pennsylvania, 1972

Flood plains that have a history of inundation or have a reasonable probability of being flooded, of course, need adequate attention in land-use planning, management, and development programs. Flood-plain maps and flood-plain-information reports are means of identifying these critical areas for special consideration.

Pennsylvania↗
USGS2014

Sex in the Suwannee, the secretive love life of Gulf Sturgeons

Mid-February in the Gulf of Mexico and a timeless ritual is about to repeat itself for perhaps the millionth time. Some mysterious signal, possibly increasing day length, flips an internal switch, feeding stops, and the homeward migration begins for the Gulf Sturgeon ( Acipenser oxyrinchus desotoi ). From far flung places along the Gulf Coast, Gulf Sturgeons start heading back to their natal rivers – they know the way instinctively. Maybe they seek out the special chemical taste of their home river, imprinted at hatching. Or perhaps the ultrasensitive electric organs decorating the underside of the snout can follow the map of the earth’s magnetic field. Either way, time to make a beeline for the welcoming waters of the Suwannee River, or maybe the Apalachicola, Choctawhatchee, or one of four other spawning rivers. Some of the adults are on a special mission – time to spawn, time to perpetuate the species. Mature males form the first wave in this homebound marathon, eager to get to the spawning grounds, eager to be the first to greet ready females with a series of sharp clicking sounds. Only spawning once each three years, females laden with large black eggs demure, taking their time, arriving in mid to late March, a month behind the early males. But most sturgeons, juveniles and immature adults not ready to spawn, are simply heading home. Not prompted by the spawning urge, they are just following the ancient annual cycle of intense winter feeding in the Gulf, followed by several months of fasting and R&R in the river.

Alabama, Florida, Georgia, Louisiana, Mississippi↗
USGS2021

A preliminary regional geomorphologic map in Utopia Planitia of the Tianwen-1 Zhurong Landing Region

A geomorphologic map is an important step to understanding the geologic context and history of a site; here, we present an initial geomorphologic map for an area spanning 22°–26°N, 108°–112°E in the Utopia Planitia (UP) region on Mars. This site is of special interest because it contains the May 2021 landing site of the Zhurong rover from Tianwen-1. Utopia Planitia exhibits many lobate features that have been proposed to be lava or mud flows. Lander and rover data should help solve the scientific question concerning the origin of UP flows. We use our map to generate an initial stratigraphic framework of geomorphological features in order to help place future Zhurong data into the regional geologic context. Our mapping effort has detailed the distribution of three geomorphologic units and 11 types of surface features.

Geophysical Research Letters↗
USGS1989

The United States Geological Survey: 1879-1989

The United States Geological Survey was established on March 3, 1879, just a few hours before the mandatory close of the final session of the 45th Congress, when President Rutherford B. Hayes signed the bill appropriating money for sundry civil expenses of the Federal Government for the fiscal year beginning July 1, 1879. The sundry civil expenses bill included a brief section establishing a new agency, the United States Geological Survey, placing it in the Department of the Interior, and charging it with a unique combination of responsibilities: 'classification of the public lands, and examination of the geological structure, mineral resources, and products of the national domain.' The legislation stemmed from a report of the National Academy of Sciences, which in June 1878 had been asked by Congress to provide a plan for surveying the Territories of the United States that would secure the best possible results at the least possible cost. Its roots, however, went far back into the Nation's history. The first duty enjoined upon the Geological Survey by the Congress, the classification of the public lands, originated in the Land Ordinance of 1785. The original public lands were the lands west of the Allegheny Mountains claimed by some of the colonies, which became a source of contention in writing the Articles of Confederation until 1781 when the States agreed to cede their western lands to Congress. The extent of the public lands was enormously increased by the Louisiana Purchase in 1803 and later territorial acquisitions. At the beginning of Confederation, the decision was made not to hold the public lands as a capital asset, but to dispose of them for revenue and to encourage settlement. The Land Ordinance of 1785 provided the method of surveying and a plan for disposal of the lands, but also reserved 'one-third part of all gold, silver, lead, and copper mines to be sold or otherwise disposed of, as Congress shall thereafter direct,' thus implicitly requiring classification of the lands into mineral and nonmineral. Mapping of the public lands was begun under the direction of the Surveyor-General, but no special provision was made for classification of the public lands, and it thus became the responsibility of the surveyor. There was,of course, no thought in 1785 or for many years thereafter of employing geologists to make the classification of the mineral lands, for geology was then only in its infancy.

Circular↗
USGS2004

Ecoregions and ecoregionalization: geographical and ecological perspectives

Ecoregions, i.e., areas exhibiting relative homogeneity of ecosystems, are units of analysis that are increasingly important in environmental assessment and management. Ecoregions provide a holistic framework for flexible, comparative analysis of complex environmental problems. Ecoregions mapping has intellectual foundations in both geography and ecology. However, a hallmark of ecoregions mapping is that it is a truly interdisciplinary endeavor that demands the integration of knowledge from a multitude of sciences. Geographers emphasize the role of place, scale, and both natural and social elements when delineating and characterizing regions. Ecologists tend to focus on environmental processes with special attention given to energy flows and nutrient cycling. Integration of disparate knowledge from the many key sciences has been one of the great challenges of ecoregions mapping, and may lie at the heart of the lack of consensus on the “optimal” approach and methods to use in such work. Through a review of the principal existing US ecoregion maps, issues that should be addressed in order to advance the state of the art are identified. Research related to needs, methods, data sources, data delivery, and validation is needed. It is also important that the academic system foster education so that there is an infusion of new expertise in ecoregion mapping and use.

Environmental Management↗
USGS2008

Interactive visualization to advance earthquake simulation

The geological sciences are challenged to manage and interpret increasing volumes of data as observations and simulations increase in size and complexity. For example, simulations of earthquake-related processes typically generate complex, time-varying data sets in two or more dimensions. To facilitate interpretation and analysis of these data sets, evaluate the underlying models, and to drive future calculations, we have developed methods of interactive visualization with a special focus on using immersive virtual reality (VR) environments to interact with models of Earth's surface and interior. Virtual mapping tools allow virtual "field studies" in inaccessible regions. Interactive tools allow us to manipulate shapes in order to construct models of geological features for geodynamic models, while feature extraction tools support quantitative measurement of structures that emerge from numerical simulation or field observations, thereby enabling us to improve our interpretation of the dynamical processes that drive earthquakes. VR has traditionally been used primarily as a presentation tool, albeit with active navigation through data. Reaping the full intellectual benefits of immersive VR as a tool for scientific analysis requires building on the method's strengths, that is, using both 3D perception and interaction with observed or simulated data. This approach also takes advantage of the specialized skills of geological scientists who are trained to interpret, the often limited, geological and geophysical data available from field observations. ?? Birkhaueser 2008.

Pure and Applied Geophysics↗
USGS2004

The U.S. Geological Survey Library

Established in 1879, to build and organize a collection of scientific materials in the earth sciences, the U.S. Geological Survey (USGS) Library is the largest earth sciences collection in the world. The USGS Library System is managed by the Geographic Information Office (GIO), Information Policy and Services Office, and includes four libraries in Reston, Va., Denver, Colo., Menlo Park, Calif., and Flagstaff, Ariz. The library holds over one million books and journals, 700,000 maps, 370,000 microforms, 270,000 pamphlets, and 250,000 photographs. In addition to the four libraries managed by the GIO, the USGS has smaller libraries in other locations with collections closely related to the specialized research of their local USGS scientists. The USGS Library System supports the research of USGS scientists by providing access to worldwide information resources. While continuing to build and maintain the large collections of maps, books, and periodicals, the USGS Library system is evolving from a traditional library to a more "virtual library." USGS employees, wherever they are located, have desktop access to an increasing wealth of electronic resources 24 hours a day, 7 days a week.

Fact Sheet↗
USGS2018

Promoting synergy in the innovative use of environmental data—Workshop summary

From December 2 to 4, 2015, NatureServe and the U.S. Geological Survey organized and hosted a biodiversity and ecological informatics workshop at the U.S. Department of the Interior in Washington, D.C. The workshop objective was to identify user-driven future directions and areas of collaboration in advanced applications of environmental data applied to forecasting and decision making for the sustainability of biodiversity and ecosystem services. Substantial effort to recruit attendees from diverse Federal, State, and private sector organizations successfully attracted participants from 20 Federal agencies and 48 different institutions in the academic, nonprofit, State government, and commercial sectors; the total number of attendees ranged from 100 to 144 during the 3-day workshop. The first one-half of the workshop was divided into 7 plenary sessions and 3 sets of lightning talk sessions organized by sector, providing 48 oral and visual plenary presentations that shared diverse perspectives on biodiversity and ecological informatics, including original biospatial analyses from 6 graduate student map contest winners. The second one-half of the workshop focused on 10 breakout sessions with participant-driven themes from the environmental data sphere and concluded with an address by the Director of the U.S. Fish and Wildlife Service. The workshop was structured to encourage interactivity. About 80–90 percent of attendees provided direct feedback using clicker devices for specific questions related to biodiversity and ecological data uses and needs, and 10 breakout session leaders shared the highlights of their group discussions during the final workshop plenary sessions. Participants were encouraged to use the Twitter hashtag #ShareUrData. Over lunch on day 2 there were 20 simultaneous presentations of tools and apps during a special “Tools Café” session. The 10 participant-defined breakout session topics are listed below: Ecosystem services and ecological indicators Inventory and monitoring Biogeographic map of the Nation Pollinators Invasive species Remote sensing Drivers of agricultural change Citizen science Climate Hydrology and watersheds Numerous common themes that emerged from the workshop include the following: The vital importance of completing foundational environmental datasets that are nationally consistent and are essential to multiple sectors, such as the Soil Survey Geographic database high-resolution soils data, a minimum 5-meter resolution digital elevation model, national hydrographic data, high-resolution land cover data, time series high-resolution spatial climate data from historical to future time steps, and a national wetland inventory. Improved, nationally consistent environmental datasets (integrated with targeted observations) will dramatically advance forecasting capacity and support early warning systems (that is, drought, forest disease); however, multiagency coordination should focus on decision support tools that convey appropriate actions and responses to adapt to, and mitigate, potential negative consequences. Digitizing and providing access to the vast stores of underused historical data that can be leveraged for this purpose is of national importance. Modern computational techniques and the ever-increasing flow of environmental data from ground and remote observations can support improved understanding of environmental change. Success of understanding patterns of change for decision making requires establishing baselines from which change can be measured. The value of digitized historical data is greater than ever before. There is a need to recognize the multifaceted potential of citizen science to engage the public in resource stewardship, to create the next generation of science, technology, engineering, math, and environmental leaders, and to have sufficient field personnel to monitor environmental trends, including early detection of alien invasive species, phenological shifts, shifting distribution and abundance of indicator species, and species inventories. The Federal government has an essential role in creating the infrastructure to dramatically improve mobilization of citizen science (and other) data by fostering the following: creation of data standards, creation of nationally consistent framework datasets, vertical integration of observation data, visualization and dissemination of aggregated datasets, and calculation and communication of derived trends. Current and near future trends in the availability of remotely sensed data (rapid expansion of satellite fleets and drones) is revolutionizing access to near-real-time ecological data. Targeted integration with ground-based observations and instrumentation has an extremely valuable role in validating remotely sensed data, filling data gaps, improving data quality, and fully realizing the potential of the near-real-time monitoring of environmental indicator trends. Integrated management of environmental data at the landscape scale is required even as specific actions on the ground are largely local in nature. The workshop highlighted numerous success stories; however, almost every breakout group pointed out the still-too-fragmented nature of the current data landscape. Management and delivery of the necessary data, tools, and analyses to sustain our Nation’s environmental capital must be a collaborative effort between Federal, State, and local governments, academia, nonprofits, and the commercial sector, even though the responsibilities of each sector are different.

Open-File Report↗
USGS1969

The Breeding Bird Survey, 1967 and 1968

In the Breeding Bird Survey of North America, cooperators ran 982 survey routes in 1967 and 1,174 in 1968. All States except Hawaii and all Canadian Provinces except Newfoundland were included. Roadside routes are selected at random within 1-degree blocks of latitude and longitude. Each 24 1/2-mile route, with 3-minute stops spaced half a mile apart, is driven by automobile. All birds heard or seen at the stops are recorded on special forms, and the data are transferred to magnetic tape for analysis. The average number of birds of each species per route is tabulated by State and Province, presenting for the first time a record of the comparative abundance of each species across the continent. The sample size is given for each species recorded. A sophisticated analysis program, here employed for the first time, is used to compute weighted mean values of the survey results for selected species at the State, stratum, regional, and continental level. The statistical significance of year-to-year changes at the 80, 90, 95, and 99 percent levels of probability are part of the computer output. An index for comparing populations of each species from year to year is established, with 1968 as the base year. Maps show the breeding range and comparative abundance of selected species.

Special Scientific Report - Wildlife↗
USGS2012

A land-use and land-cover modeling strategy to support a national assessment of carbon stocks and fluxes

Changes in land use, land cover, disturbance regimes, and land management have considerable influence on carbon and greenhouse gas (GHG) fluxes within ecosystems. Through targeted land-use and land-management activities, ecosystems can be managed to enhance carbon sequestration and mitigate fluxes of other GHGs. National-scale, comprehensive analyses of carbon sequestration potential by ecosystem are needed, with a consistent, nationally applicable land-use and land-cover (LULC) modeling framework a key component of such analyses. The U.S. Geological Survey has initiated a project to analyze current and projected future GHG fluxes by ecosystem and quantify potential mitigation strategies. We have developed a unique LULC modeling framework to support this work. Downscaled scenarios consistent with IPCC Special Report on Emissions Scenarios (SRES) were constructed for U.S. ecoregions, and the FORE-SCE model was used to spatially map the scenarios. Results for a prototype demonstrate our ability to model LULC change and inform a biogeochemical modeling framework for analysis of subsequent GHG fluxes. The methodology was then successfully used to model LULC change for four IPCC SRES scenarios for an ecoregion in the Great Plains. The scenario-based LULC projections are now being used to analyze potential GHG impacts of LULC change across the U.S.

Applied Geography↗
USGS2007

Risk-targeted versus current seismic design maps for the conterminous United States

The probabilistic portions of the seismic design maps in the NEHRP Provisions (FEMA, 2003/2000/1997), and in the International Building Code (ICC, 2006/2003/2000) and ASCE Standard 7-05 (ASCE, 2005a), provide ground motion values from the USGS that have a 2% probability of being exceeded in 50 years. Under the assumption that the capacity against collapse of structures designed for these "uniformhazard" ground motions is equal to, without uncertainty, the corresponding mapped value at the location of the structure, the probability of its collapse in 50 years is also uniform. This is not the case however, when it is recognized that there is, in fact, uncertainty in the structural capacity. In that case, siteto-site variability in the shape of ground motion hazard curves results in a lack of uniformity. This paper explains the basis for proposed adjustments to the uniform-hazard portions of the seismic design maps currently in the NEHRP Provisions that result in uniform estimated collapse probability. For seismic design of nuclear facilities, analogous but specialized adjustments have recently been defined in ASCE Standard 43-05 (ASCE, 2005b). In support of the 2009 update of the NEHRP Provisions currently being conducted by the Building Seismic Safety Council (BSSC), herein we provide examples of the adjusted ground motions for a selected target collapse probability (or target risk). Relative to the probabilistic MCE ground motions currently in the NEHRP Provisions, the risk-targeted ground motions for design are smaller (by as much as about 30%) in the New Madrid Seismic Zone, near Charleston, South Carolina, and in the coastal region of Oregon, with relatively little (<15%) change almost everywhere else in the conterminous U.S.

Conference Paper↗