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At least 793 records · Page 44Linked to original sources
USGS2008

Geomorphic map of Worcester County, Maryland, interpreted from a LIDAR-based, digital elevation model

A recently compiled mosaic of a LIDAR-based digital elevation model (DEM) is presented with geomorphic analysis of new macro-topographic details. The geologic framework of the surficial and near surface late Cenozoic deposits of the central uplands, Pocomoke River valley, and the Atlantic Coast includes Cenozoic to recent sediments from fluvial, estuarine, and littoral depositional environments. Extensive Pleistocene (cold climate) sandy dune fields are deposited over much of the terraced landscape. The macro details from the LIDAR image reveal 2 meter-scale resolution of details of the shapes of individual dunes, and fields of translocated sand sheets. Most terrace surfaces are overprinted with circular to elliptical rimmed basins that represent complex histories of ephemeral ponds that were formed, drained, and overprinted by younger basins. The terrains of composite ephemeral ponds and the dune fields are inter-shingled at their margins indicating contemporaneous erosion, deposition, and re-arrangement and possible internal deformation of the surficial deposits. The aggregate of these landform details and their deposits are interpreted as the products of arid, cold climate processes that were common to the mid-Atlantic region during the Last Glacial Maximum. In the Pocomoke valley and its larger tributaries, erosional remnants of sandy flood plains with anastomosing channels indicate the dynamics of former hydrology and sediment load of the watershed that prevailed at the end of the Pleistocene. As the climate warmed and precipitation increased during the transition from late Pleistocene to Holocene, dune fields were stabilized by vegetation, and the stream discharge increased. The increased discharge and greater local relief of streams graded to lower sea levels stimulated down cutting and created the deeply incised valleys out onto the continental shelf. These incised valleys have been filling with fluvial to intertidal deposits that record the rising sea level and warmer, more humid climate in the mid-Atlantic region throughout the Holocene. Thus, the geomorphic details provided by the new LIDAR DEM actually record the response of the landscape to abrupt climate change. Holocene trends and land-use patterns from Colonial to modern times can also be interpreted from the local macro- scale details of the landscape. Beyond the obvious utility of these data for land-use planning and assessments of resources and hazards, the new map presents new details on the impact of climate changes on a mid-latitude, outer Coastal plain landscape.

Maryland↗
USGS1981

Morphology and processes associated with the accumulation of the fine-grained sediment deposit on the southern New England shelf

A 13,000 km 2 area of the southern New England Continental Shelf which is covered by anomalously fine-grained sediment has been surveyed by means of high-resolution, seismic-reflection and side-scan sonar techniques to map its morphology and structure, and a near-bottom instrument system contributed to understanding present activity of the deposit. Seismic-reflection profiles show that the fine-grained deposit, which is as much as 13 m thick, has accumulated during the last transgression because it rests on a reflector that is geomorphically similar to and continuous with the Holocene transgressive sand sheet still exposed on the shelf to the west. The ridge and swale topography comprising the sand sheet on the shelf off New Jersey and Long Island are relict in origin as these same features are found buried under the fine sediment deposit. Southwestward migrating megaripples observed on the sonographs in the eastern part of the deposit are evidence that sediment is still actively accumulating in this area. In the western part of the deposit, where surface sediment is composed of silt plus clay, evidence of present sediment mobility consists of changes in the near-bottom, suspended-matter concentrations primarily associated with storms. Nantucket Shoals and Georges Bank are thought to be the sources for the fine-textured sediment. Storms and strong tidal currents in these shoal areas may still erode available fine-grained material, which then is transported westward by the mean drift to the southern New England Shelf, where a comparatively tranquil environment permits deposition of the fine material.

Journal of Sedimentary Petrology↗
USGS2006

Georgia's Surface-Water Resources and Streamflow Monitoring Network, 2006

The U.S. Geological Survey (USGS) network of 223 real-time monitoring stations, the 'Georgia HydroWatch,' provides real-time water-stage data, with streamflow computed at 198 locations, and rainfall recorded at 187 stations. These sites continuously record data on 15-minute intervals and transmit the data via satellite to be incorporated into the USGS National Water Information System database. These data are automatically posted to the USGS Web site for public dissemination (http://waterdata.usgs.gov/ga/nwis/nwis). The real-time capability of this network provides information to help emergency-management officials protect human life and property during floods, and mitigate the effects of prolonged drought. The map at right shows the USGS streamflow monitoring network for Georgia and major watersheds. Streamflow is monitored at 198 sites statewide, more than 80 percent of which include precipitation gages. Various Federal, State, and local agencies fund these streamflow monitoring stations.

Georgia↗
USGS2010

Streamflow of 2009--Water year summary

The maps and graph in this summary describe streamflow conditions for water-year 2009 (October 1, 2008 to September 30, 2009) in the context of the 80-year period 1930-2009, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's National Streamflow Information Program. The period 1930-2009 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. Each of the maps and graphs can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.

Fact Sheet↗
USGS2012

Land-use and land-cover scenarios and spatial modeling at the regional scale

Land-use and land-cover (LULC) change has altered a large part of the earth's surface. Scenarios of potential future LULC change are required in order to better manage potential impacts on biodiversity, carbon fluxes, climate change, hydrology, and many other ecological processes. The U.S. Geological Survey is analyzing potential future LULC change in the United States, using an approach based on scenario construction and spatially explicit modeling. Similar modeling techniques are being used to produce historical LULC maps from 1940 to present. With the combination of backcast and forecast LULC data, the USGS is providing consistent LULC data for historical, current, and future time frames to support a variety of research applications.

Fact Sheet↗
USGS2022

Nebraska and Landsat

The rolling plains of Nebraska occupy a storied place in the American psyche. For those living outside the Midwest, the Cornhusker State may be seen as a symbol of the Nation’s heartland, cropped border to border, with country churches and barely standing barns to be found around every turn of its gravel roads. Although the pioneer history and agricultural heritage of the 37th State lend credence to this idyllic view, Nebraska’s varied landscapes and modern economy make the reality of life in the State more complex than its rural image would suggest. Agriculture remains Nebraska’s top industry, but manufacturing now represents 12 percent of the State’s gross domestic product. The financial services and insurance industries account for 8 percent of the gross domestic product in Nebraska, which is the headquarters of Berkshire Hathaway and Mutual of Omaha, the latter of which is named after Nebraska’s largest city, which grew nearly 12 percent between 2010 and 2020. Cropland is indeed a prominent feature in Nebraska, but the State also is home to 8 State parks, 5 national parks, 2 national forests, and 3 national grasslands. The grasses and dunes of the Nebraska Sand Hills that stretch across the north-central quarter of the State are a National Natural Landmark. Data from the Landsat satellite program contribute to the study and management of Nebraska’s land in myriad ways, from monitoring crop productivity and aiding in rangeland management to tracking damage from floods, droughts, or hurricanes. Land cover maps produced using data pulled from the 50-year Landsat archive can offer important insights into urban growth, land use trends, and land change patterns. Here are a few examples of how Landsat has been used in Nebraska.

Nebraska↗
USGS1984

Reconnaissance geology of the Qufar Quadrangle, sheet 27/41 D, Kingdom of Saudi Arabia

The Qufar quadrangle, south of the city of Ha' il in the northern Arabian Shield is underlain by late Proterozoic granitic and dioritic rocks and two volcano-sedimentary sequences. Phanerozoic rocks include a few outcrops of the Cambrian and Ordovician Saq Sandstone and small remnants of Miocene basalt flows and plugs. The oldest rocks in the quadrangle comprise the Nuf formation, a layered sequence of submarine, tholeiitic metabasalt and meta-andesite, and interbedded metagraywacke and marble. The Nuf formation may correlate with rocks mapped as Halaban or Hulayfah group (approximately 780-720 Ma old) to the south of the quadrangle. Cogenetic subvolcanic rocks include gabbro and diorite. Voluminous plutonic rocks of approximately monzogranite composition intruded and dismembered the Nuf formation, gabbro, and diorite, which were simultaneously metamorphosed and internally deformed. Metamorphism of the Nuf formation was variable, but generally' upper greenstone-facies assemblages were produced. Following a period of extensive erosion, the Hadn formation, dacitic to rhyolitic ignimbrite and flow breccia, and interbedded subgraywacke, arkose, and minor conglomerate was deposited. The Hadn formation may be a continental equivalent of the Murdama group, which is mapped to the south of the quadrangle and is approximately 650 to 610 Ma old. Numerous plutons, predominantly monzogranite, but ranging from gabbro to alkali-feldspar granite, post-date the Hadn formation. Of these, the Malayhah granite is particularly noteworthy because it has a broad zone of cataclasis along the western and southern border. Country rock within several kilometers of the western contact is also highly sheared, predominantly along northerly trends. Locally, a melange of several rock types was produced. Contact metamorphism to garnet-amphibolite hornfels facies occurred at this time, and may be responsible for the formation of small sub-economic magnetite lenses interlayered with some of the marbles of the Nuf formation. In the northern part of the quadrangle, southeast dipping imbricate thrust faults probably closely post-date the emplacement of the Mulayhah granite. These thrusts were followed in time by predominantly northeast-trending high-angle faults. The last major plutonic event in the area is the intrusion of the alkalic granite complexes at Jabal Aja and Jabal Sal ma about 580 Ma ago. Of particular note is a per alkalic border facies of the Jabal Aja complex that is associated with pegmatites enriched in thorium, niobium, and rare-earth elements.

Open-File Report↗
USGS1998

Front Range Infrastructure Resources Project: water-resources activities

Infrastructure, such as roads, buildings, airports, and dams, is built and maintained by use of large quantities of natural resources such as aggregate (sand and gravel), energy, and water. As urban area expand, local sources of these resource are becoming inaccessible (gravel cannot be mined from under a subdivision, for example), or the cost of recovery of the resource becomes prohibitive (oil and gas drilling in urban areas is costly), or the resources may become unfit for some use (pollution of ground water may preclude its use as a water supply). Governmental land-use decision and environmental mandates can further preclude development of natural resources. If infrastructure resources are to remain economically available. current resource information must be available for use in well-reasoned decisions bout future land use. Ground water is an infrastructure resource that is present in shallow aquifers and deeper bedrock aquifers that underlie much of the 2,450-square-mile demonstration area of the Colorado Front Range Infrastructure Resources Project. In 1996, mapping of the area's ground-water resources was undertaken as a U.S. Geological Survey project in cooperation with the Colorado Department of Natural Resources, Division of Water Resources, and the Colorado Water Conservation Board.

Colorado↗
USGS2009

Streamflow of 2008--Water year summary

The maps and graphs appearing in this summary describe streamflow conditions for water-year 2008 (October 1, 2007 to September 30, 2008) in the context of the 79-year period 1930-2008, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National Streamflow Information Program. The period 1930-2008 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. The runoff value for a geographic area is computed as the median runoff value for all streamgages in that geographic area. For example, the runoff value for a State is the median for all streamgages in that State, and the median for the Nation is the median value for all streamgages in the Nation. Each of the maps and graphs below can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.

Fact Sheet↗
USGS2011

Streamflow of 2010--Water year summary

The maps and graph in this summary describe streamflow conditions for water-year 2010 (October 1, 2009 to September 30, 2010) in the context of the 81-year period 1930-2010, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National Streamflow Information Program. The period 1930-2010 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. Each of the maps and graphs below can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.

Fact Sheet↗
USGS2012

Streamflow of 2011 - Water year summary

The maps and graph in this summary describe streamflow conditions for water year 2011 (October 1, 2010, to September 30, 2011) in the context of the 82-year period from 1930 through 2011, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National Streamflow Information Program (http://water.usgs.gov/nsip/). The period 1930-2010 was used because, prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. Each of the maps and graphs can be expanded to a larger view by clicking on the image. In all of the graphics, a rank of 1 indicates the highest flow of all years analyzed.

Fact Sheet↗
USGS2022

A user guide to selecting invasive annual grass spatial products for the western United States

Invasive annual grasses (IAGs)—including Bromus tectorum (cheatgrass), Taeniatherum caput-medusae (medusahead), and Ventenata dubia (ventenata) species—present significant challenges for rangeland management by altering plant communities, impacting ecosystem function, reducing forage for wildlife and livestock, and increasing fire risk. Numerous spatial data products are used to map IAGs, and understanding the similarities, differences, and potential tradeoffs among these products is key to selecting the right maps for specific applications. This short guide outlines considerations for selecting regional- and national-scale spatial data to support the management of IAGs.

western United States↗
USGS2022

Landslides in Minnesota

Landslides in Minnesota have caused loss of life, damaged infrastructure, and negatively affected Minnesota’s natural resources. Landslides increase the amount of sediment contributed to lakes and rivers, with negative consequences for water quality and aquatic habitats. Recent mapping reveals that landslide susceptible areas within Minnesota primarily occur on steep slopes adjacent to rivers, lakes, and transportation corridors. Local variation in landslide susceptibility is related to the underlying geology and glacial history.

Minnesota↗
USGS2016

U.S. Geological Survey collections—Preserving the past to inform the future: Tour three federal repositories—Core Research Center, Paleontological Collection, and the NSF National Ice Core Laboratory

This 2016 Geological Society of America (GSA) Annual Meeting trip will explore the Core Research Center, Paleontological Collection, and National Science Foundation National Ice Core Laboratory—three collections of major national signifi cance managed by the U.S. Geological Survey (USGS). Since its inception in 1879, USGS has collected, preserved, and managed physical collections for scientifi c investigations of Earth’s systems. The Core Research Center is the largest federal core repository in the United States, where over 74 million meters (242 million feet) of the subsurface are represented by the collection of rock cores and well cuttings, available for use by researchers investigating resource potential, tectonics, structures, aquifers, and more. The USGS has conducted paleontological research for more than 110 years to inform geological mapping, biostratigraphy, paleoecology, paleoclimate, and other research. Most of these paleontological samples are at the Smithsonian Institution National Museum of Natural History (NMNH) and USGS Denver facilities. The USGS Denver paleontological collection includes ~1.2 million samples. Ancillary materials consisting of handwritten ledgers, index cards, fi eld reports, maps, and other information produced by USGS investigators provide profound knowledge about the specimens and associated geological systems. The USGS is working with NMNH to systematically digitize the collection to preserve and expose samples and data to research. The National Science Foundation (NSF) National Ice Core Laboratory (NICL) is the nation’s repository for preserving, archiving, and sampling meteoric ice cores collected from the world’s ice sheets, ice caps, and glaciers, mostly from Antarctica and Greenland. NICL’s primary mission is to store and curate ice cores, primarily collected during NSF-sponsored projects, for present and future sample investigations.

Colorado↗
USGS2022

Landsat Collection 2 Level-3 Fractional Snow Covered Area science product

The Landsat Collection 2 Level-3 Fractional Snow Covered Area science product indicates the percentage of pixels covered by snow for Landsat 4–9 imagery. Landsat’s spatial resolution offers the capability to map snow cover patterns across topographically complex mountainous regions. Snow cover is spatially and temporally variable and is often concentrated in remote or inaccessible land regions, making spaceborne remote sensing the most feasible approach to measure and monitor snow cover change.

Fact Sheet↗
USGS1992

Jurassic ash-flow sheets, calderas, and related intrusions of the Cordilleran volcanic arc in southeastern Arizona: Implications for regional tectonics and ore deposits

Volcanologic, petrologic, and paleomagnetic studies of widespread Jurassic ash-flow sheets in the Huachuca-southern Dragoon Mountains area have led to identification of four large source calderas and associated comagmatic intracaldera intrusions. Stratigraphic, facies, and contact features of the caldera-related tuffs also provide constraints on the locations, lateral displacements, and very existence for some major northwest-trending faults and inferred regional thrusts in south-eastern Arizona. For example, the intricate Cochise thrust system, as mapped by others in the southern Dragoon Mountains, consists instead of primary depositional contacts within caldera-fill megabreccia, and the inferred regional thrusts do not exist, at least as previously interpreted. Silicic alkalic compositions of the Jurassic caldera-related, ash-flow tuffs; bimodal associated mafic magmatism; and interstratified coarse sedimentary deposits provide evidence for synvolcanic extension and rifting within the Cordilleran magmatic arc. Gold-copper mineralization is associated with subvolcanic intrusions at several of the Jurassic calderas.

Arizona↗
USGS2003

The U.S. Geological Survey Land Remote Sensing Program

In 2002, the U. S. Geological Survey (USGS) launched a program to enhance the acquisition, preservation, and use of remotely sensed data for USGS science programs, as well as for those of cooperators and customers. Remotely sensed data are fundamental tools for studying the Earth's land surface, including coastal and near-shore environments. For many decades, the USGS has been a leader in providing remotely sensed data to the national and international communities. Acting on its historical topographic mapping mission, the USGS has archived and distributed aerial photographs of the United States for more than half a century. Since 1972, the USGS has acquired, processed, archived, and distributed Landsat and other satellite and airborne remotely sensed data products to users worldwide. Today, the USGS operates and manages the Landsats 5 and 7 missions and cooperates with the National Aeronautics and Space Administration (NASA) to define and implement future satellite missions that will continue and expand the collection of moderate-resolution remotely sensed data. In addition to being a provider of remotely sensed data, the USGS is a user of these data and related remote sensing technology. These data are used in natural resource evaluations for energy and minerals, coastal environmental surveys, assessments of natural hazards (earthquakes, volcanoes, and landslides), biological surveys and investigations, water resources status and trends analyses and studies, and geographic and cartographic applications, such as wildfire detection and tracking and as a source of information for The National Map. The program furthers these distinct but related roles by leading the USGS activities in providing remotely sensed data while advancing applications of such data for USGS programs and a wider user community.

Fact Sheet↗
USGS2008

Modeling and dynamic monitoring of ecosystem performance in the Yukon River Basin

Central Alaska is ecologically sensitive and experiencing stress in response to marked regional warming. Resource managers would benefit from an improved ability to monitor ecosystem processes in response to climate change, fire, insect damage, and management policies and to predict responses to future climate scenarios. We have developed a method for analyzing ecosystem performance as represented by the growing season integral of normalized difference vegetation index (NDVI), which is a measure of greenness that can be interpreted in terms of plant growth or photosynthetic activity (gross primary productivity). The approach illustrates the status and trends of ecosystem changes and separates the influences of climate and local site conditions from the influences of disturbances and land management. We emphasize the ability to quantify ecosystem processes, not simply changes in land cover, across the entire period of the remote sensing archive (Wylie and others, 2008). The method builds upon remotely sensed measures of vegetation greenness for each growing season. By itself, however, a time series of greenness often reflects annual climate variations in temperature and precipitation. Our method seeks to remove the influence of climate so that changes in underlying ecological conditions are identified and quantified. We define an "expected ecosystem performance" to represent the greenness response expected in a particular year given the climate of that year. We distinguish "performance anomalies" as cases where the ecosystem response is significantly different from the expected ecosystem performance. Maps of the performance anomalies (fig. 1) and trends in the anomalies give valuable information on the ecosystems for land managers and policy makers at a resolution of 1 km to 250 m.

Fact Sheet↗