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At least 487 records · Page 27Linked to original sources
USGS2016

The 3D Elevation Program: summary for Puerto Rico

Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, scientific research, national security, recreation, and many others. For the Commonwealth of Puerto Rico, elevation data are critical for flood risk management, landslide mitigation, natural resources conservation, sea level rise and subsidence, coastal zone management, infrastructure and construction management, and other business uses. Today, high-density light detection and ranging (lidar) data are the primary sources for deriving elevation models and other datasets. Federal, State, Tribal, U.S. territorial, and local agencies work in partnership to (1) replace data that are older and of lower quality and (2) provide coverage where publicly accessible data do not exist. A joint goal of State and Federal partners is to acquire consistent, statewide coverage to support existing and emerging applications enabled by lidar data. The National Enhanced Elevation Assessment evaluated multiple elevation data acquisition options to determine the optimal data quality and data replacement cycle relative to cost to meet the identified requirements of the user community. The evaluation demonstrated that lidar acquisition at quality level 2 for the conterminous United States, Hawaii, and selected U.S. territories, and quality level 5 interferometric synthetic aperture radar (IfSAR) data for Alaska, all with a 6- to 10-year acquisition cycle, provided the highest benefit/cost ratios. The 3D Elevation Program (3DEP) initiative selected an 8-year acquisition cycle for the respective quality levels. 3DEP, managed by the U.S. Geological Survey (USGS), the Office of Management and Budget Circular A‒16 lead agency for terrestrial elevation data, responds to the growing need for high-quality topographic data and a wide range of other three-dimensional (3D) representations of the Nation’s natural and constructed features.

Puerto Rico↗
USGS2016

Assessing potential scour using the South Carolina bridge-scour envelope curves

Summary Bridge-scour equations presented in the Federal Highway Administration Hydraulic Engineering Circular No. 18 reflect the current state-of-the practice for predicting scour at bridges. Although these laboratory-derived equations provide an important resource for assessing scour potential, there is a measure of uncertainty when applying these equations to field conditions. The uncertainty and limitations have been acknowledged by laboratory researchers and confirmed in field investigations. Because of the uncertainty associated with bridge-scour equations, HEC-18 recommends that engineers evaluate the computed scour depths obtained from the equations and modify the resulting data if they appear unreasonable. Perhaps the best way to evaluate the reasonableness of predicted scour is to compare it to field measurements of historic scour. Historic field data show scour depths resulting from high flows and provide a reference for evaluating predicted scour. It is rare, however, that such data are available at or near a site of interest, making the evaluation of predicted scour as compared to field data difficult if not impossible. Realizing the value of historic scour measurements, the U.S. Geological Survey (USGS), in cooperation with the South Carolina Department of Transportation (SCDOT), conducted a series of three field investigations to collect historic scour data with the goal of understanding regional trends of scour at riverine bridges in South Carolina. Historic scour measurements, including measurements of clear-water abutment, contraction, and pier scour, as well as live-bed contraction and pier scour, were made at more than 200 bridges. These field investigations provided valuable insights into regional scour trends and yielded regional bridge-scour envelope curves that can be used as supplementary tools for assessing all components of scour at riverine bridges in South Carolina. The application and limitations of these envelope curves were documented in four reports. Because each report addresses different components of bridge scour, it was recognized that there was a need to develop an integrated procedure for applying the envelope curves to help assess scour potential at riverine bridges in South Carolina. The result of that effort is detailed in Benedict and others (2016) and summarized in this fact sheet.

South Carolina↗
USGS2022

National assessment of carbon dioxide enhanced oil recovery and associated carbon dioxide retention resources — Summary

Introduction In 2020, the U.S. Geological Survey (USGS) completed a probabilistic assessment of the volume of technically recoverable oil resources that might be produced by using current carbon dioxide enhanced oil recovery (CO 2 -EOR) technologies in amenable conventional oil reservoirs underlying the onshore and State waters areas of the conterminous United States. The assessment also includes estimates of the mass of CO 2 that could be stored (retained) in the assessed oil reservoirs following the application of the CO 2 -EOR process. The USGS assessment team evaluated more than 3,500 oil reservoirs that were miscible to injected CO 2 . The assessed reservoirs are in 185 previously defined USGS plays in 33 petroleum provinces of 7 national regions. The team estimated that the total technically recoverable oil resulting from the application of the CO 2 -EOR process ranges from approximately 25,000 million barrels (MMbbl) at the P 5 percentile to as much as 32,000 MMbbl at the P 95 percentile, with a mean of 29,000 MMbbl. The associated CO 2 retention ranges from approximately 7,400 million metric tons (Mt) at the P 5 percentile to as much as 9,500 Mt at the P 95 percentile, with a mean of 8,400 Mt. The results are summarized in this fact sheet and are provided in more detail in the companion data release and circular. The West Texas and Eastern New Mexico region (primarily its Permian Basin) and the Gulf Coast region together contain 60 percent of the mean assessed CO 2 -EOR oil potential and 61 percent of the mean assessed CO 2 retention. Other regions with significant resource potential include the Midcontinent region and the Rocky Mountains and Northern Great Plains region.

Continental United States↗
USGS2013

Lake Mead--clear and vital

“Lake Mead – Clear and Vital” is a 13 minute documentary relating the crucial role of science in maintaining high water quality in Lake Mead. The program was produced coincident with release of the Lakes Mead and Mohave Circular a USGS publication covering past and on-going research in the lakes and tributaries of the Lake Mead National Recreation Area.

Nevada↗
USGS2018

Cooperative Fish and Wildlife Research Units Program—2017 year in review postcard

This postcard provides details about the Cooperative Fish and Wildlife Research Units Program—2017 Year in Review, U.S. Geological Survey Circular 1438, now available at https://doi.org/10.3133/cir1438 . In this report, you will find details about the Cooperative Fish and Wildlife Research Units (CRU) Program relating to its background, fish and wildlife science, students, staffing, vacancies, research funding, outreach and training, science themes, accolades, and professional services. You will see snapshots of CRU projects with information on how results have been or are being applied by cooperators. This is the essence of what we do: science that matters. Throughout the year, keep up with CRU research projects at http://www.coopunits.org .

General Information Product↗
USGS2019

Cooperative Fish and Wildlife Research Units program—2018 year in review postcard

This postcard provides details about the "Cooperative Fish and Wildlife Research Units Program—2018 Year in Review," U.S. Geological Survey Circular 1452, now available at https://doi.org/10.3133/cir1452 . In this report, you will find details about the Cooperative Fish and Wildlife Research Units (CRU) program relating to its background, fish and wildlife science, students, staffing, vacancies, research funding, outreach and training, science themes, accolades, and professional services. You will see snapshots of CRU projects with information on how results have been or are being applied by cooperators. This is the essence of what we do: science that matters. Throughout the year, keep up with CRU research projects at http://www.coopunits.org .

General Information Product↗
USGS2020

Cooperative Fish and Wildlife Research Units program—2019 year in review postcard

Acting Chief’s Message Dear friends, I invite you to take a look at U.S. Geological Survey Circular 1463, “Cooperative Fish and Wildlife Research Units Program—2019 Year in Review,” now available at https://doi.org/10.3133/cir1463 . In this report, you will find details about the Cooperative Fish and Wildlife Research Units (CRU) program concerning fish and wildlife science, students, staffing, vacancies, research funding, outreach and training, awards, accolades, and professional services. You will also see examples of unit projects with information on how results have been or are being applied by our cooperators. Throughout the year, keep up with our research projects at https://www1.usgs.gov/coopunits/Headquarters/ . Regards, John D. Thompson

General Information Product↗
USGS1977

Geologic map of the Eridania Quadrangle of Mars

The Eridania quadrangle is located within the densely cratered terrain of the southern hemisphere of Mars, east of the large circular Hellas Basin. The areas contain three distinct physiographic provinces that div ide the quadrangle into latitud in al belts. The northern part of the quadrangle is dominated by cratered upland plateau, the central part by plains, the southern part by a mottled surface of rugged topography and a high density of craters subdued by erosion. In general, the oldest geologic unit occurs in the upland terrain, the youngest in the central lowlands. Large contrast in albedo were observed on Mars from Earth long before Mariner spaceflight missions. The most conspic uous of these features within the quadrangle are areas of low albedo in the north and in the south that corresponds to the two main belts of high-relief terrain. The intervening region of high albedo corresponds to the central plains belt, also an area of recurrent seasonal frost. The southern polar cap extends to about 50 ˚ S lat and includes all of the southern belt of high relief.

IMAP↗
USGS1980

Geologic map of the Argyre quadrangle of Mars

The geology of the Argyre quadrangle of Mars is dominated by the conspicuous Argyre basin, defined by a rim of rugged mountain blocks that surround a nearly circular expanse of plains 800 km across. Of the large (greater than 500 km in diameter) basins identified on Mars, Argyre is the best preserved and possibly youngest. Basins appear to be traps for eolian debris and evidently are source areas for some of the dust storms that periodically envelop the planet. The quadrangle lies within the densely cratered province that characterizes the southern hemisphere, contrasting with sparsely cratered plains generally confined to the northern hemisphere. Northwest of Argyre an outlier of sparsely cratered, ridged plains extends into the quadrangle from the Coprates region. Northeast of the basin are the cratered uplands, parts of which are presumed to represent remnants of the earliest martian crust (Wilhelms, 1974). South of the quadrangle the cratered plateau is replaced by the pitted, etched, layered, and mantled terrains that characterize the south polar region (Sharp, 1973a; Condit and Soderblom, 1978). Constructional volcanic landforms were not recognized within the map area.

IMAP↗
USGS1986

Geologic map of the western equatorial region of Mars

The r egional topographic swell centered in the Tharsis Montes and Syria Planum extends over one-third of the map area (U.S. Geological Survey, 1976). Within this high region are the four largest and youngest volcanoes on Mars: Olympus Mons, Arsia Mons, Pavonis Mons, and Ascrae us Mons. The latter three collectively form the large northeast-trending, volcanic mountain chain of the Tharsis Montes. This volcanic chain lies athwart the global highland - lowland boundary that transects the western equatorial region. The boundary, where not covered b young lava flow s, is marked by a gentle, irregular scarp bordered by clusters of low knobby hills. It separates the relatively smooth, flat, spar sely cratered northern plains from the higher, rougher, more densely cratered plateau terrain of the southern highlands . A vast system of canyons, the Valles Marineris , originates in Noctis Labyrinthus , just east of the Tharsis -Sy ria swell, and extends eastward for several thousand kilo meters. Ancient rivers channels appear to have sources in canyons and chaotic terrain north of Valles Ma rineris and in a large fissure at the head of the Mangala V alles. Visible remnants of large circular basins are not as common on Mars as on the Moon, probably because of more active erosion and deeper burial on Mars by eolian and fluvial activity and by widespread volcanism on both the highlands and plains. The youngest and b est preserved impact basin on Mars, lying in the western hemisphere , is more than 1,00 0 km across. It has a broad flat floor ( Argyre Planitia) covered by eolian materials and volcanic flows ; the floor is several kilometers below its encompassing rough mountainous rim.

IMAP↗
USGS1998

Geologic map of the MTM -85280 quadrangle, Planum Australe region of Mars

The polar deposits on Mars are of great interest because they probably record martian climate variations (Thomas and others, 1992). The area shown on this map includes polar layered deposits with distinct low-albedo features and a sharp boundary between the layered deposits and the moderately cratered unit that forms the floor of Chasma Australe. Detailed mapping of this quadrangle was undertaken to further investigate the geologic relations between the albedo features and the layered deposits and to better constrain the recent geologic history of the south polar region. Dark dunes in the north polar region appear to be derived from erosion of the layered deposits, but the source of dark material in the south polar region is less clear (Thomas and Weitz, 1989). The presence of dark material in the brighter, redder layered deposits is paradoxical (Herkenhoff and Murray, 1990a); resolving this paradox is likely to result in a better understanding of the origin and evolution of the layered deposits and, therefore, the mechanisms by which global climate variations are recorded. Published geologic maps of the south polar region of Mars have been based on images acquired by either Mariner 9 (Condit and Soderblom, 1978; Scott and Carr, 1978) or the Viking Orbiters (Tanaka and Scott, 1987). The extent of the layered deposits mapped previously from Mariner 9 data is different from that mapped using Viking Orbiter images, and the present map agrees with the map by Tanaka and Scott (1987): the floor of Chasma Australe is not mapped as layered deposits. The residual polar ice cap, areas of partial frost cover, the layered deposits, and two nonvolatile surface units - the dust mantle and the dark material - were mapped by Herkenhoff and Murray (1990a) at 1:2,000,000 scale using a color mosaic of Viking Orbiter images. This mosaic and an additional Viking color mosaic were used to confirm the identification of the nonvolatile Amazonian units for this map and to test hypotheses for their origin and evolution. The colors and albedos of these units, as measured in places outside this map area, are presented in table 1 and figure 1. Accurately measuring the color and albedo of the units in this map area was not possible due to low signal/noise in the part of the red/violet mosaic (corrected for atmospheric scattering) that includes this area (Herkenhoff and Murray, 1990a). However, color/albedo unit boundaries in this area are visible in color mosaics that have not been corrected for atmospheric scattering effects. Therefore, while the color and albedo of various units on this map cannot be precisely quantified and compared with the values in table 1 and figure 1, color/albedo units can still be recognized. Because the resolution of the color mosaics is not sufficient to map these units in detail at 1:500,000 scale, contacts between them were recognized and mapped using higher resolution black-and-white Viking and Mariner 9 images. Only two possible impact craters in the layered deposits have been found in the area mapped; both are slightly elongate rather than circular. One, 1.6 km in diameter at lat 86.6° S., long 268°, was recognized by Plaut and others (1988); the other, about 3 km in diameter, is at lat 82.8° S., long 277°. Although the crater statistics are poor (only 16 likely impact craters found in the entire south polar layered deposits), these observations generally support the conclusions that the south polar layered deposits are Late Amazonian in age and that some areas have been exposed for at least 120 million years (Plaut and others, 1988; Herkenhoff and Murray, 1992, 1994). However, the recent cratering flux on Mars is poorly constrained, so inferred ages of surface units are uncertain. The Viking Orbiter 2 images used to construct the base were taken during the southern summer of 1977, with resolutions no better than 180 m/pixel. (The "less than 100 m per picture element" in Notes on Base of the controlled photomosaic base [U.S. Geological Survey, 1986] is incorrect.) A digital mosaic of Mariner 9 images was also constructed to aid in mapping. The Mariner 9 images were taken during the southern summer of 1971-72 and have resolutions as high as 90 m/pixel. However, usefulness of the Mariner 9 mosaic is limited by incomplete coverage and atmospheric dust opacity.

IMAP↗
USGS2002

Geological map of the Kaiwan Fluctus Quadrangle (V-44), Venus

Introduction The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the Venusian atmosphereon October 12, 1994. Magellan had the objectives of: (1) improving knowledge of the geologic processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving knowledge of the geophysics of Venus by analysis of Venusian gravity. The Magellan spacecraft carried a 12.6-cm radar system to map the surface of Venus. The transmitter and receiver systems were used to collect three datasets: synthetic aperture radar (SAR) images of the surface, passive microwave thermal emission observations, and measurements of the backscattered power at small angles of incidence, which were processed to yield altimetric data. Radar imaging and altimetric and radiometric mapping of the Venusian surface were done in mission cycles 1, 2, and 3, from September 1990 until September of 1992. Ninety-eight percent of the surface was mapped with radar resolution of approximately 120 meters. The SAR observations were projected to a 75-m nominal horizontal resolution; these full-resolution data compose the image base used in geologic mapping. The primary polarization mode was horizontal-transmit, horizontal receive (HH), but additional data for selected areas were collected for the vertical polarization sense. Incidence angles varied from about 20? to 45?. High-resolution Doppler tracking of the spacecraft was done from September 1992 through October 1994 (mission cycles 4, 5, 6). High-resolution gravity observations from about 950 orbits were obtained between September 1992 and May 1993, while Magellan was in an elliptical orbit with a periapsis near 175 kilometers and an apoapsis near 8,000 kilometers. Observations from an additional 1,500 orbits were obtained following orbit-circularization in mid-1993. These data exist as a 75? by 75? harmonic field.

IMAP↗
USGS2003

Geologic map of the Rusalka Planitia Quadrangle (V-25), Venus

The Rusalka Planitia quadrangle (herein referred to as V-25) occupies an 8.1 million square kilometer swath of lowlands nestled within the eastern highlands of Aphrodite Terra on Venus. The region (25?-0? N., 150?-180? E.) is framed by the crustal plateau Thetis Regio to the southwest, the coronae of the Diana-Dali chasmata complex to the south, and volcanic rise Atla Regio to the west. Regions to the north, and the quadrangle itself, are part of the vast lowlands, which cover four-fifths of the surface of Venus. The often-unspectacular lowlands of Venus are typically lumped together as ridged or regional plains. However, detailed mapping reveals the mode of resurfacing in V-25's lowlands: a mix of corona-related flow fields and local edifice clusters within planitia superimposed on a background of less clearly interpretable extended flow fields, large volcanoes, probable corona fragments, and edifice-flow complexes. The history detailed within the Rusalka Planitia quadrangle is that of the extended evolution of long-wavelength topographic basins in the presence of episodes of extensive corona-related volcanism, pervasive low-intensity small-scale eruptions, and an early phase of regional circumferential shortening centered on central Aphrodite Terra. Structural reactivation both obscures and illuminates the tectonic development of the region. The data are consistent with progressive lithospheric thickening, although the critical lack of an independent temporal marker on Venus severely hampers our ability to test this claim and correlate between localities. Two broad circular basins dominate V-25 geology: northern Rusalka Planitia lies in the southern half of the quadrangle, whereas the smaller Llorona Planitia sits along the northwestern corner of V-25. Similar large topographic basins occur throughout the lowlands of Venus, and gravity data suggest that some basins may represent dynamic topography over mantle downwellings. Both planitiae include coronae and associated lava flows, as well as fields of volcanic shields. Within each basin, the local geologic histories are relatively well constrained; correlations between the planitiae are difficult without making assumptions. The region between the two basins contains large volcanoes, corona fragments, deformation belts, and shield fields embedded within a topographically higher heterogeneous expanse of rolling plains. V-25's most prominent structural grain is a suite of wrinkle ridges that arc around the southwest corner of the quadrangle. A patchy suite of northeast-trending assorted lineaments underlies much of the map area. Although these lineaments originally were narrow fractures, this structural suite appears to have subsequently opened up along extensional troughs near Corpman crater in the southwest corner of the map area and been reactivated as wrinkle ridges at Ran Colles in the middle of the southern boundary of V-25. Nineteen impact craters dot the quadrangle. Craters Yazruk, du Chatelet, and Caccini contribute large geology- obscuring ejecta halos. Crater densities are too low for either relative or absolute age dating. Ten splotches, presumably associated with meteor airbursts, also occur across V-25.

IMAP↗
USGS1967

(LAC-93) Geologic map of the Mare Humorum region of the moon

The principal feature of the Mare Humorum region is the Humorum basin, a circular mare basin approximately 200 km (kilometer) in diameter . The basin formed early in the history of the moon and was later flooded by mare material. Impact cratering with attendant erosion and aggradation and episod ic volcanism and faulting have occurred in the region . The inferred history of the Humorum basin is similar to that of the Imbrium basin ( S hoemaker and Hackman, 1962; Titley , 1964), but the more subdued topography and the larger density of craters on the rim of the Humorum basin suggest that it is older than the Imbrium basin.

IMAP↗
USGS1971

Geologic map of the Bonpland PQC region of the Moon

This geologic map has been prepared from the photographic data returned by Ranger VII and is one of a series prepared from the data returned by the Ranger VII, VIII, and IX spacecraft. The map area, in Mare Cognitum, includes the Ranger VII impact point. The map shows the geologic relationship of surface units at the distal end of a ray from either the crater Tycho (Shoemaker, 1965, p. 86) or the crater Copernicus (U.S. Geol. Survey, 1971). None of the craters nor the surface detail have been resolved on Earth-based photographs; the map area appears as only a faintly bright spot on high-quality full-Moon photographs. The oldest materials recognized are those which once formed the level mare surface. These materials have been comminuted by impact and modified by shock, radiation, solar wind, and temperature effects. They are interpreted to have originally been volcanic. Superposed on the mare material is a cluster of elongate craters (unit ce). The topographic forms and surface characteristics of this unit appears to be contiguous with a belt of the south of similar forms and characteristics. In the map area, parallel to subparallel north-trending subdued craters and very gentle depressions, generally deepest and most pronounced at their north ends, are the most conspicuous landforms. They lack prominent rims and are not as distinct as typical circular craters of the same size. Their floors are irregular in profile, and walls are gently sloping. This form, the consistent alignment of the elongated craters, and the fact the belt of elongated craters extends to the south suggest the impact of a group of objects traveling at low velocities and low trajectory angles after ejection from Tycho, about 1,000 km to the south.

IMAP↗
USGS1972

Geologic map of the Taruntius Quadrangle of the Moon

The distribution of major physiographic provinces and geologic units of the Tarant ius quadrangle is determined by the five intersecting circular multi-ringed mare basin s. Three basins, i n probable order of decreasing age, are Tran quill itatis , Fecun ditatis , Serenitatis, Nectaris , and Crisiu m . The uplifted ring structures of the basin form terra mountains, peninsulas , and islands, and the depressions between the uplifts are the major deposition sites of post -basin terra and mare material.

IMAP↗
USGS1980

Map showing the Elko crater field, Elko County, Nevada

The Elko crater field consists of two arrays of rimmed craters in the valleys of Dorsey, Susie, and McClellan Creeks, 30 to 50 km north of Elko, Nevada. In the principal array, more the 165 craters are scattered irregularly in an area 3 km wide and 20 km long. Most of the the craters are circular but some, formed by overlap, are oval or irregular. They range from 5 m to 250 m in diameter and the relief of the largest ones, from the sedimentary floor of the cater to the top of the rim, is at least 6 m. The surficial material of the rims is principally gravel similar to that in the surrounding terrane. The surficial material inside the craters is primarily silt, probably blown in by the wind, and pebbles, apparently washed in from the rims. There is also a later of volcanic ash at a depth of about 2 m. This ash was identified by its physical and mineralogical composition as the Mazama ash (R. E. Wilcox, oral commun., 1976), a ±6600 year old ash bed also present in the alluvium of Dorsey and Susie Creeks. The craters are presently interpreted as having been formed by a meteor shower although no meteor material has been discovered. Investigation is continuing.

Nevada↗
USGS1988

Aeromagnetic and gravity anomaly maps and a hydrothermal veins favorability map of the Wallace 1 degree by 2 degrees Quadrangle, Montana and Idaho

This map is part of a folio of maps of the Wallace 1° x 2° quadrangle, Montana and Idaho, compiled as part of the Conterminous united States Mineral Assessment Program (CUSMAP). Background information about this folio is published in U.S. Geological Survey Circular 920. CUSMAP is designed to systematically assess the mineral resource potential of selected 1° x 2° quadrangles at a scale of 1:250,000. The objectives of CUSMAP are (1) to gather, interpret, and disseminate information about the geology and mineral resources for land-use planning and resource management, and (2) to provide framework information for planning more detailed research and exploration programs.

Idaho, Montana↗