USGS Science⌕ Search

SEARCH · USGS Science

Results for “Paper”

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

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,675 records · Page 93Linked to original sources
USGS2002

Examples of landscape indicators for assessing environmental conditions and problems in urban and suburban areas

Geo-indicators can help to assess environmental conditions in city urban and suburban areas. Those indicators should be meaningful for understanding environmental changes. From examples of Spanish and American cities, geo-indicators for assessing environmental conditions and changes in urban and suburban areas are proposed. The paper explore two types of geo-indicators. The first type presents general information that can be used to indicate the presence of a broad array of geologic conditions, either favouring or limiting various kinds of uses of the land. The second type of geo-indicator is the one most commonly used, and as a group most easily understood; these are site and problem specific and they are generally used after a problem is identified. Among them, watershed processes, seismicity and physiographic diversity are explained in more detail. A second dimension that is considered when discussing geo-indicators is the issue of scale. Broad scale investigations, covering extensive areas are only efficient at cataloguing general conditions common to much of the area or some outstanding feature within the area. This type of information is best used for policy type decisions. Detailed scale investigations can provide information about local conditions, but are not efficient at cataloguing vast areas. Information gathered at the detailed level is necessary for project design and construction.

Conference Paper↗
USGS2002

Model Performance of Water-Current Meters

The measurement of discharge in natural streams requires hydrographers to use accurate water-current meters that have consistent performance among meters of the same model. This paper presents the results of an investigation into the performance of four models of current meters - Price type-AA, Price pygmy, Marsh McBirney 2000 and Swoffer 2100. Tests for consistency and accuracy for six meters of each model are summarized. Variation of meter performance within a model is used as an indicator of consistency, and percent velocity error that is computed from a measured reference velocity is used as an indicator of meter accuracy. Velocities measured by each meter are also compared to the manufacturer's published or advertised accuracy limits. For the meters tested, the Price models werer found to be more accurate and consistent over the range of test velocities compared to the other models. The Marsh McBirney model usually measured within its accuracy specification. The Swoffer meters did not meet the stringent Swoffer accuracy limits for all the velocities tested.

Conference Paper↗
USGS2002

Velocity and Sediment Concentration Measurements over Bedforms in Sand-Bed Rivers

Bedforms often are present on the bed of alluvial sand-bed rivers. Bedforms, such as dunes, impact the flow field. In this field study, velocity and suspended-sediment concentration measurements were made longitudinally along a dune field in large (5-15 meters deep) alluvial sand-bed rivers. The velocity and suspended-sediment concentration data was collected using an acoustic Doppler current profiler, acoustic Doppler velocimeters, an optical backscatter sensor, and, two sediment intakes. This paper presents a description of these measurement devices and techniques for the collection of this data. Some preliminary results observed at the Missouri River at St. Charles, Missouri are presented.

Conference Paper↗
USGS2003

Linking Proxy-Based and Datum-Based Shorelines on a High-Energy Coastline: Implications for Shoreline Change Analyses

A primary purpose of this paper is to quantitatively link variously defined and derived shoreline estimates commonly used for shoreline change analysis. Estimates of shoreline mapping and derivation error, natural shoreline variability, and the relationships between horizontally-derived (proxy-based) shorelines to vertical datums (e.g. MHW) are presented. A series of shoreline repeatability and variability experiments as well as data from a beach monitoring program along the high-energy US Pacific Northwest coast, indicate total uncertainty estimates of the horizontal position of proxy-based shorelines to be approximately ?? 50-150 m for T-sheets and aerial photography and approximately ?? 15 m for datum-based shorelines derived from ground- or air-based topographic surveys. The ability to obtain reliable shoreline change results depends upon both the selected shoreline definition (e.g. horizontal- or feature-based proxy, or datum-based intercept) and the accuracy of the technique used in mapping or interpreting its position. The position of the selected shoreline on the beach profile determines its inherent temporal and spatial variability, an important consideration that has often been overlooked in the scientific literature on shoreline change, Historical shorelines mapped on NOS T-sheets and aerial photos have commonly identified high water line (HWL)-type shorelines, which are shown to be higher on the beach surface than the MHW-datum intercept along coasts subject to wave runup. Analyses of 4.5 years of beach profile data from the southwest Washington coast suggest that both the MHW and HWL-type shorelines have greater natural short-term variability than expected, significantly greater than the variability of shoreline proxies defined farther landward and higher on the beach profile. A model for determining the natural variability of HWL-type shorelines reveals that this short-term variability is the dominant factor in the large total uncertainty values associated with shorelines derived from T-sheets and aerial photographs. The results of these analyses and quantitative comparisons are relevant to determining the significance of historical shoreline changes, as well as to defining the appropriate shoreline proxy or datum and time scale for future shoreline change analysis.

Conference Paper↗
USGS2003

US National Large-scale City Orthoimage Standard Initiative

The early procedures and algorithms for National digital orthophoto generation in National Digital Orthophoto Program (NDOP) were based on earlier USGS mapping operations, such as field control, aerotriangulation (derived in the early 1920's), the quarter-quadrangle-centered (3.75 minutes of longitude and latitude in geographic extent), 1:40,000 aerial photographs, and 2.5 D digital elevation models. However, large-scale city orthophotos using early procedures have disclosed many shortcomings, e.g., ghost image, occlusion, shadow. Thus, to provide the technical base (algorithms, procedure) and experience needed for city large-scale digital orthophoto creation is essential for the near future national large-scale digital orthophoto deployment and the revision of the Standards for National Large-scale City Digital Orthophoto in National Digital Orthophoto Program (NDOP). This paper will report our initial research results as follows: (1) High-precision 3D city DSM generation through LIDAR data processing, (2) Spatial objects/features extraction through surface material information and high-accuracy 3D DSM data, (3) 3D city model development, (4) Algorithm development for generation of DTM-based orthophoto, and DBM-based orthophoto, (5) True orthophoto generation by merging DBM-based orthophoto and DTM-based orthophoto, and (6) Automatic mosaic by optimizing and combining imagery from many perspectives.

Conference Paper↗
USGS2003

Use of microstrip patch antennas in grain permittivity measurement

In this paper, a compact size free-space setup is proposed for the measurement of complex permittivity of granular materials. The horn antennas in the conventional setup are replaced by microstrip patch antennas which is a step toward system miniaturization. The experimental results obtained are in good agreement with those obtained with horn antennas.

Conference Paper↗
USGS2004

Data dictionary and formatting standard for dissemination of geotechnical data

A pilot system for archiving and web dissemination of geotechnical data collected and stored by various agencies is currently under development. Part of the scope of this project, sponsored by the Consortium of Organizations for Strong-Motion Observation Systems (COSMOS) and by the Pacific Earthquake Engineering Research Center (PEER) Lifelines Program, is the development of a data dictionary and formatting standard. This paper presents the data model along with the basic structure of the data dictionary tables for this pilot system.

Conference Paper↗
USGS2004

Development of a consortium for water security and safety: Planning for an early warning system

The events of September 11, 2001 have raised concerns over the safety and security of the Nation's critical infrastructure including water and waste water systems. In June 2002, the U.S. EPA's Region II Office (New York City), in response to concerns over water security, in collaboration with Rutgers University agreed to establish a Regional Drinking Water Security and Safety Consortium (RDWSSC). Members of the consortium include: Rutgers University's Center for Information Management, Integration and Connectivity (CIMIC), American Water (AW), the Passaic Valley Water Commission (PVWC), the North Jersey District Water Supply Commission (NJDWSC), the N.J. Department of Environmental Protection, the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agencies, Region II Office. In December of 2002 the consortium members signed a memorandum of understanding (MOU) to pursue activities to enhance regional water security. Development of an early warning system for source and distributed water was identified as being of primary importance by the consortium. In this context, an early warning system (EWS) is an integrated system of monitoring stations located at strategic points in a water utilities source waters or in its distribution system, designed to warn against contaminants that might threaten the health and welfare of drinking water consumers. This paper will discuss the consortium's progress in achieving these important objectives.

Conference Paper↗
USGS2004

Analysis of summer 2002 melt extent on the Greenland ice sheet using MODIS and SSM/I data

Previous work has shown that the summer of 2002 had the greatest area of snow melt extent on the Greenland ice sheet ever recorded using passive-microwave data. In this paper, we compare the 0?? isotherm derived from the Moderate-Resolution Imaging Spectroradiometer (MODIS) instrument, with Special Sensor Microwave/Imager (SSM/I)-derived melt, at the time of the maximum melt extent in 2002. To validate the MODIS-derived land-surface temperatures (LSTs), we compared the MODIS LSTs with air temperatures from nine stations (using 11 different data points) and found that they agreed to within 2.3??2.09??C, with station temperatures consistently lower than the MODIS LSTs. According to the MODIS LST, the maximum surface melt extended to ???2300 m in southern Greenland; while the SSM/I measurements showed that the maximum melt extended to nearly 2700 m in southeastern Greenland. The MODIS and SSM/I data are complementary in providing detailed information about the progression of surface and near-surface melt on the Greenland ice sheet.

Conference Paper↗
USGS2004

Development of regional liquefaction-induced deformation hazard maps

This paper describes part of a project to assess the feasibility of producing regional (1:24,000-scale) liquefaction hazard maps that are based-on potential liquefaction-induced deformation. The study area is the central Santa Clara Valley, at the south end of San Francisco Bay in Central California. The information collected and used includes: a) detailed Quaternary geological mapping, b) over 650 geotechnical borings, c) probabilistic earthquake shaking information, and d) ground-water levels. Predictions of strain can be made using either empirical formulations or numerical simulations. In this project lateral spread displacements are estimated and new empirical relations to estimate future volumetric and shear strain are used. Geotechnical boring data to are used to: (a) develop isopach maps showing the thickness of sediment thatis likely to liquefy and deform under earthquake shaking; and (b) assess the variability in engineering properties within and between geologic map units. Preliminary results reveal that late Holocene deposits are likely to experience the greatest liquefaction-induced strains, while Holocene and late Pleistocene deposits are likely to experience significantly less horizontal and vertical strain in future earthquakes. Development of maps based on these analyses is feasible.

Conference Paper↗
USGS2004

Characterization of single-walled carbon nanotubes for environmental implications

Adsorption capacities of N2 and various organic vapors (methyl-ethyl ketone (MEK), toluene, and cyclohexane) on select electric-arc and HiPco produced single walled carbon nanotubes (SWNT) were measured at 77 and 298 K, respectively. The amount of N2 adsorbed on a SWNT sample depended on the sample purity, methodology, and on the sample age. Adsorption capacities of organic vapors (100-1000 ppm vol) on SWNT in humid conditions were much higher than those for microporous activated carbons. These results established a foundation for additional studies related to potential environmental applications of SWNT. The MEK adsorption capacities of samples EA95 and CVD80 and mesoporous tire-derived activated carbon in humid conditions were lower than in dry conditions. This is an abstract of a paper presented at the AIChE Annual Meeting (Austin, TX 11/7-12/2004).

Conference Paper↗
USGS2004

Updated United Nations Framework Classification for reserves and resources of extractive industries

The United Nations have studied how the oil and gas resource classification developed jointly by the SPE, the World Petroleum Congress (WPC) and the American Association of Petroleum Geologists (AAPG) could be harmonized with the United Nations Framework Classification (UNFC) for Solid Fuel and Mineral Resources (1). The United Nations has continued to build on this and other works, with support from many relevant international organizations, with the objective of updating the UNFC to apply to the extractive industries. The result is the United Nations Framework Classification for Energy and Mineral Resources (2) that this paper will present. Reserves and resources are categorized with respect to three sets of criteria: ??? Economic and commercial viability ??? Field project status and feasibility ??? The level of geologic knowledge The field project status criteria are readily recognized as the ones highlighted in the SPE/WPC/AAPG classification system of 2000. The geologic criteria absorb the rich traditions that form the primary basis for the Russian classification system, and the ones used to delimit, in part, proved reserves. Economic and commercial criteria facilitate the use of the classification in general, and reflect the commercial considerations used to delimit proved reserves in particular. The classification system will help to develop a common understanding of reserves and resources for all the extractive industries and will assist: ??? International and national resources management to secure supplies; ??? Industries' management of business processes to achieve efficiency in exploration and production; and ??? An appropriate basis for documenting the value of reserves and resources in financial statements.

Conference Paper↗
USGS2004

Illinois drainage water management demonstration project

Due to naturally high water tables and flat topography, there are approximately 4 million ha (10 million ac) of farmland artificially drained with subsurface (tile) systems in Illinois. Subsurface drainage is practiced to insure trafficable field conditions for farm equipment and to reduce crop stress from excess water within the root zone. Although drainage is essential for economic crop production, there have been some significant environmental costs. Tile drainage systems tend to intercept nutrient (nitrate) rich soil-water and shunt it to surface water. Data from numerous monitoring studies have shown that a significant amount of the total nitrate load in Illinois is being delivered to surface water from tile drainage systems. In Illinois, these drainage systems are typically installed without control mechanisms and allow the soil to drain whenever the water table is above the elevation of the tile outlet. An assessment of water quality in the tile drained areas of Illinois showed that approximately 50 percent of the nitrate load was being delivered through the tile systems during the fallow period when there was no production need for drainage to occur. In 1998, a demonstration project to introduce drainage water management to producers in Illinois was initiated by NRCS4 An initial aspect of the project was to identify producers that were willing to manage their drainage system to create a raised water table during the fallow (November-March) period. Financial assistance from two federal programs was used to assist producers in retrofitting the existing drainage systems with control structures. Growers were also provided guidance on the management of the structures for both water quality and production benefits. Some of the retrofitted systems were monitored to determine the effect of the practice on water quality. This paper provides background on the water quality impacts of tile drainage in Illinois, the status of the demonstration project, preliminary monitoring results, and other observations.

Conference Paper↗
USGS2004

Correlative weighted stacking for seismic data in the wavelet domain

Horizontal stacking plays a crucial role for modern seismic data processing, for it not only compresses random noise and multiple reflections, but also provides a foundational data for subsequent migration and inversion. However, a number of examples showed that random noise in adjacent traces exhibits correlation and coherence. The average stacking and weighted stacking based on the conventional correlative function all result in false events, which are caused by noise. Wavelet transform and high order statistics are very useful methods for modern signal processing. The multiresolution analysis in wavelet theory can decompose signal on difference scales, and high order correlative function can inhibit correlative noise, for which the conventional correlative function is of no use. Based on the theory of wavelet transform and high order statistics, high order correlative weighted stacking (HOCWS) technique is presented in this paper. Its essence is to stack common midpoint gathers after the normal moveout correction by weight that is calculated through high order correlative statistics in the wavelet domain. Synthetic examples demonstrate its advantages in improving the signal to noise (S/N) ration and compressing the correlative random noise.

Conference Paper↗
USGS2004

Baseline practices and user needs for Web dissemination of geotechnical data

This paper presents the findings and recommendations of the User Scenario Work Group (USWG) in identifying a baseline of current practices within the geo-professional community and prioritizing desired functional requirements in the development of a comprehensive geotechnical information management system. This work was conducted as an initial phase of a larger project to demonstrate the effectiveness of a web based virtual data center for the dissemination of geotechnical data from multiple linked databases of various government and private sector organizations. An online survey was administered over the course of several months to practitioners across the nation. The results from the survey were compiled and examined to provide direction to the other project teams in the development of user-driven prototype data system.

Conference Paper↗
USGS2004

Physical habitat and sediment in the lower Virgin River

The Virgin River in southwestern Utah and adjacent Arizona and Nevada is habitat for a number of endangered and threatened species of fish. The river also has significant loads of sediment that change the characteristic of the stream channel with time. The Virgin River transports large quantities of sand. Some sections of the river store the sand in the stream bed following a high stream flow event; the sediment is then removed by lower streamflows that can cause a wave of sand to pass through river channels in other sections of the river. The Hurricane Bridge on the Virgin River had a sand wave that passed through the channel during a low flow event that followed a high flow event. This paper demonstrates that antecedent conditions are important in the analysis of physical habitat in sand-bed rivers because the relation between the streamflows and habitat will change depending on these antecedent conditions.

Conference Paper↗
USGS2004

Continuous thermochemical conversion process to produce oil from swine manure

Thermochemical conversion (TCC) of livestock manure is a novel technology that has shown very promising results in treating waste and producing oil. A batch TCC system that was previously developed successfully converted 70% of swine manure volatile solids to oil and reduced manure chemical oxygen demand by ??? 75%. The necessary retention time to achieve an oil product was largely dependent on the operating temperature. The highest oil production efficiency was 80% of the volatile solids (or 70 wt % of the total solids). The average carbon and hydrogen contents were ??? 72 and 9%, respectively. The heating values for 80% of the oil products ranged from 32,000 to 36,700 kJ/kg. This is an abstract of a paper presented at the AWMA 97th Annual Conference and Exhibition (Indianapolis, IN 6/22-25/2004).

Conference Paper↗
USGS2004

Issues of scale, location and geologic terrain related to Salt Lake City and Baltimore-Washington metropolitan areas

Planning and development of expanding metropolitan regions require consideration of earth science issues related to issues involving scale, space (location), geologic terrain and physiographic units, and information transfer. This paper explores these matters with examples from the Salt Lake City, Utah area and Mid-Atlantic region of Baltimore-Washington that include water supply and natural hazards (earthquakes, landslides, and sinkholes.) Information transfer methods using physiographic units at national, regional, local and site scales serve to communicate relevant geologic constraint and natural resource information.

Conference Paper↗