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

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At least 1,117 records · Page 62Linked to original sources
USGS2013

Integrating stations from the North America Gravity Database into a local GPS-based land gravity survey

The ability to augment local gravity surveys with additional gravity stations from easily accessible national databases can greatly increase the areal coverage and spatial resolution of a survey. It is, however, necessary to integrate such data seamlessly with the local survey. One challenge to overcome in integrating data from national databases is that these data are typically of unknown quality. This study presents a procedure for the evaluation and seamless integration of gravity data of unknown quality from a national database with data from a local Global Positioning System (GPS)-based survey. The starting components include the latitude, longitude, elevation and observed gravity at each station location. Interpolated surfaces of the complete Bouguer anomaly are used as a means of quality control and comparison. The result is an integrated dataset of varying quality with many stations having GPS accuracy and other reliable stations of unknown origin, yielding a wider coverage and greater spatial resolution than either survey alone.

Missouri↗
USGS2012

Preseismic and coseismic deformation associated with the Hollister, California, earthquake of November 28, 1974

The epicenter of the Hollister earthquake ( M L = 5.1) of November 28, 1974, is located near the center of an 81‐line trilateration network which has been surveyed annually since 1971. Five lines in the neighborhood of the epicenter were surveyed just 2 days before the earthquake, and two other lines nearby were surveyed 48 days earlier. Although some of these measurements suggest a possible preearthquake anomaly in line length, the anomaly is within the uncertainty in measurement. A comparison of the most recent preearthquake survey (June 1974) and the most immediate postearthquake survey (December 1974 to January 1975) of the entire network indicates a uniform linear contraction of about 0.8 ppm. This is most reasonably attributed to survey error even though a systematic error of that magnitude is unexpected. We conclude that no demonstrable preseismic or coseismic deformation was detected and suggest that an upper limit for these phenomena is less than 1 ppm in line length. A reasonable dislocation model for the Hollister earthquake yields coseismic changes in line length not greater than a few parts in 10 7 , well below the limit of detection in Geodolite surveys.

California↗
USGS2014

Appendix B—The work of the United States Geological Survey and cooperating agencies on ground water for war purposes

A report by O. E. MEINZER, published as Appendix B of the annual report of the Committee for 1942–43 [Trans. Amer. Geophys. Union, Part II, pp. 418–420, 1943], describes in some detail the previous work of the United States Geological Survey and cooperating agencies on ground water for war purposes. The geologists from the staff of the Geological Survey listed in that report and several other ground‐water geologists have served in the Army during the past year on water‐supply assignments. Only sketchy and unofficial information is as yet available concerning the activities of these geologists, but it is believed that they are now all engaged in overseas theaters of warfare and that their services in water‐supply and other technical work are of substantial value. In this service they have been supported by ground‐water maps and reports furnished by the Geological Survey for the different theaters.

Eos, Transactions, American Geophysical Union↗
USGS1967

Hydraulic testing techniques of deep drill holes at Pahute Mesa, Nevada test site

This report describes the testing techniques used by the U. S. Geological Survey to obtain hydrologic data in deep holes drilled in volcanic rocks at Pahute Mesa, Nevada Test Site. The testing program in each hole includes geophysical logging, pumping, and injecting and swabbing between straddle packers. Rock lithologies and qualitative data on hydrologic conditions in the borehole are obtained from electric, caliper, temperature, and fluid resistivity logs. Quantitative data on major water-yielding intervals in the borehole are obtained from radioactive tracer and spinner surveys. Pumping tests are made to measure the combined yield of the various aquifers. Injection and swabbing tests are made by adding known volumes of water to, or withdrawing known volumes of water from, straddle-packed intervals and observing the rate of decline or rise in water level resulting from this injection or withdrawal of water. The yield of tested intervals is stated as relative specific capacity, in units of gallons per minute per foot of drawdown.

Open-File Report↗
USGS1999

Borehole-geophysical characterization of a fractured-bedrock aquifer, Rye, New Hampshire

Borehole geophysical logs collected from six wells were analyzed to characterize a high-yield bedrock aquifer in the Town of Rye, New Hampshire. Video camera, caliper, fluid temperature and conductivity, natural gamma, and deviation logs were used to identify and characterize the fractured bedrock. More advanced geophysical tools included acoustic televiewer and borehole radar, which were used to determine the orientation of fractures and fracture zones that intersect and surround each of the six wells. Borehole-radar surveys included single-hole directional-reflection surveys. The borehole radar logs indicate that the bedrock aquifer is highly fractured. Zones of low velocity and high attenuation in the radar logs correlated with the fractures and fracture zones observed in the standard geophysical logs of the six wells. The strikes of the fracture sets, as determined by the acoustic televiewer, coincide with photolineaments identified on high-altitude and low-altitude aerial photography and side-looking airborne radar (SLAR). The coincident fracture sets and lineaments trend N100°E, N140°E, N170°E, and N40°E.

New Hampshire↗
USGS2002

Rationale and operational plan to upgrade the U.S. gravity database

A concerted effort is underway to prepare a substantially upgraded digital gravity anomaly database for the United States and to make this data set and associated usage tools available on the internet. This joint effort, spearheaded by the geophysics groups at the National Imagery and Mapping Agency (NIMA), University of Texas at El Paso (UTEP), U.S. Geological Survey (USGS), and National Oceanic and Atmospheric Administration (NOAA), is an outgrowth of the new geoscientific community initiative called Geoinformatics (www.geoinformaticsnetwork.org). This dominantly geospatial initiative reflects the realization by Earth scientists that existing information systems and techniques are inadequate to address the many complex scientific and societal issues. Currently, inadequate standardization and chaotic distribution of geoscience data, inadequate accompanying documentation, and the lack of easy-to-use access tools and computer codes for analysis are major obstacles for scientists, government agencies, and educators. An example of the type of activities envisioned, within the context of Geoinformatics, is the construction, maintenance, and growth of a public domain gravity database and development of the software tools needed to access, implement, and expand it. This product is far more than a high quality database; it is a complete data system for a specific type of geophysical measurement that includes, for example, tools to manipulate the data and tutorials to understand and properly utilize the data. On August 9, 2002, twenty-one scientists from the federal, private and academic sectors met at a workshop to discuss the rationale for upgrading both the United States and North American gravity databases (including offshore regions) and, more importantly, to begin developing an operational plan to effectively create a new gravity data system. We encourage anyone interested in contributing data or participating in this effort to contact G.R. Keller or T.G. Hildenbrand. This workshop was the first step in building a web-based data system for sharing quality gravity data and methodology, and it builds on existing collaborative efforts. This compilation effort will result in significant additions to and major refinement of the U.S. database that is currently released publicly by NOAA’s National Geophysical Data Center and will also include an additional objective to substantially upgrade the North American database, released over 15 years ago (Committee for the Gravity Anomaly Map of North America, 1987).

Open-File Report↗
USGS1992

Map, tables, and summary of fossil and isotopic age data, Mount Hayes Quadrangle, eastern Alaska range, Alaska

This report describes, summarizes, and interprets all known bedrock fossil and isotopic age studies for the Mount Hayes quadrangle, eastern Alaska Range, Alaska. The accompanying map shows the location of all known bedrock fossil and isotopic sample localities in the quadrangle on a generalized geologic base map. These fossil and isotopic age data are obtained from new studies, unpublished data of the U.S. Geological Survey, contributed unpublished data, and published data. This report is one result of a five-year mineral resource assessment of the quadrangle that was done during the summers of 1978 through 1982, with additional topical studiesin 1985 and 1986. This report is one part of a folio on the geological, geochemical, geophysical, and mineral-resource assessment studies of the quadrangle prepared as part of the Alaskan Mineral Resource Assessment Program (AMRAP) of the U.S. Geological Survey.

Alaska↗
USGS2002

Geology, Geochemistry and Geophysics of Sedimentary Rock-Hosted Au Deposits in P.R. China

This is the second report concerning results of a joint project between the U.S. Geological Survey and the Tianjin Geological Academy to study sedimentary rock-hosted Au deposits in P.R. China. Since the 1980s, Chinese geologists have devoted a large-scale exploration and research effort to the deposits. As a result, there are more than 20 million oz of proven Au reserves in sedimentary rock-hosted Au deposits in P.R. China. Additional estimated and inferred resources are present in over 160 deposits and occurrences, which are undergoing exploration. This makes China second to Nevada in contained ounces of Au in Carlin-type deposits. It is likely that many of the Carlin-type Au ore districts in China, when fully developed, could have resource potential comparable to the multi-1,000-tonne Au resource in northern Nevada. The six chapters of this report describe sedimentary rock-hosted Au deposits that were visited during the project. Chapters 1 and 2 provide an overview of sedimentary rock-hosted Au deposits and Carlin-type Au deposits and also provide a working classification for the sedimentary rock-hosted Au deposits. Chapters 3, 4, and 5 provide descriptions that were compiled from the literature in China in three main areas: the Dian-Qian-Gui, the Qinling fold belt, and Middle-Lower Yangtze River areas. Chapter 6 contains a weights-of-evidence (WofE), GIS-based mineral assessment of sedimentary rock-hosted Au deposits in the Qinling fold belt and Dian-Qian-Gui areas. Appendices contain scanned aeromagnetic (Appendix I) and gravity (Appendix II) geophysical maps of south and central China. Data tables of the deposits (Appendix III) also are available in the first report as an interactive database at http://geopubs.wr.usgs.gov/open-file/of98-466/. Geochemical analysis of ore samples from the deposits visited are contained in Appendix IV.

Open-File Report↗
USGS2013

Cold-seep habitat mapping: high-resolution spatial characterization of the Blake Ridge Diapir seep field

Relationships among seep community biomass, diversity, and physiographic controls such as underlying geology are not well understood. Previous efforts to constrain these relationships at the Blake Ridge Diapir were limited to observations from piloted deep-submergence vehicles. In August 2012, the autonomous underwater vehicle (AUV) Sentry collected geophysical and photographic data over a 0.131 km2 area at the Blake Ridge Diapir seeps. A nested survey approach was used that began with a regional or reconnaissance-style survey using sub-bottom mapping systems to locate and identify seeps and underlying conduits. This survey was followed by AUV-mounted sidescan sonar and multibeam echosounder systems mapping on a mesoscale to characterize the seabed physiography. At the most detailed survey level, digital photographic imaging was used to resolve sub-meter characteristics of the biology. Four pockmarks (25–70 m diameter) were documented, each supporting chemosynthetic communities. Concentric zonation of mussels and clams suggests the influence of chemical gradients on megafaunal distribution. Data collection and analytical techniques used here yield high-resolution habitat maps that can serve as baselines to constrain temporal evolution of seafloor seeps, and to inform ecological niche modeling and resource management.

Deep-Sea Research Part II: Topical Studies in Ocea↗
USGS1980

High-resolution seismic-reflection profiling data from the inner continental shelf of southeastern Massachusetts

Six hundred-seventy kilometers of closely spaced high-resolution seismic-­reflection data have been collected from eastern Rhode Island Sound and Vineyard Sound, Mass, by the U.S. Geological Survey in cooperation with the Massachusetts Department of Public Works. These data were obtained during the June 1975 cruise of the R/V ASTERIAS as part of a continuing regional study of the Massachusetts offshore area to assess potential mineral resources, to evaluate environmental impact of mining of resources and of offshore disposal of solid waste and harbor dredge-spoil materials, and to map the offshore geology and shallow structure. The data were obtained by using a surface-towed EG&G Unit Pulse Boomer* (300 joules: 400 Hz-8kHz frequency) sound source. Reflected acoustic energy was detected by a 4.6-m, a-element hydrophone array, was amplified, was actively filtered (400 Hz-4kHz bandpass), and was graphically displayed on an EPC* dry paper recorder at a 0.25-second sweep rate. System resolution was generally 1 to 1.5 m. Navigational control was provided by Loran C (posi­tional accuracy within 0.2 km) and was supplemented by radar and visual fixes. Positional information was logged at 15-minute intervals and at major course changes. The original records may be examined at the Data Library, U.S. Geological Survey, Woods Hole, MA 02543. Microfilm copies of the data are available for purchase from the National Geophysical and Solar-Terrestrial Data Center (NGSDC), Boulder, CO 80302.

Open-File Report↗
USGS1980

Side-scan sonograph data from eastern Rhode Island Sound and Vineyard Sound, Massachusetts

Two hundred twenty-four kilometers of closely spaced side-scan sono­graph data have been collected from eastern Rhode Island Sound and Vineyard Sound, Mass., by the U.S. Geological Survey in cooperation with the New England Division of the U.S. Army Corps of Engineers. These data were obtained during the August 1976 cruise of the B./V A. E. VERRILL as part of a continuing regional study of the Massachusetts offshore area to determine the suitability and potential environmental effect of ocean dumping of large volumes of harbor dredge-spoil material. Specifically, as part of a proposed Federal Harbor improvement and maintenance dredging of Fall River and Mt. Hope Bay, Mass. under the juris­diction of the Army Corps of Engineers, the disposal of the resultant dredge spoil is planned for an ocean dump site located in eastern Rhode Island Sound. The proposed site is also under consideration as a "regional" disposal grounds to be utilized by State and private organizations performing dredging work authorized by the Corps. The data were obtained by using a Klein Side Scan Towfish* (sonar fre­quency, 100 kHz; pulse length, 0.1 msec). Signal returns from the starboard and port scans were automatically tuned, texture-enhanced, and printed center­out on 2 channels of a 3-channel Klein* wet-paper graphic recorder. Scan ranges of 75 m and 150 m were used. For comparison of graphic display, incoming signals from the starboard scan were also recorded on the third channel using a manual (nonautomatic) tuning mode. Navigational control was provided by Loran -C (positional accuracy within 0.2 km). Positional information was logged at 15-minute intervals and at major course changes. The original records may be examined at the Data Library, U.S. Geological Survey, Woods Hole, MA 02543. Microfilm copies of the data are available for purchase from the National Geophysical and Solar-Terrestrial Data Center (NGSDC), Boulder, CO 80302.

Open-File Report↗
USGS1980

Single-channel seismic-reflection profiles from Massachusetts coastal waters and the western part of Georges Bank

The U.S. Geological Survey collected approximately 1,200 km each of airgun and minisparker single-channel seismic-reflection profiles during the R/V FAY cruise 023 in September 1976. The purpose of the 6-day cruise was to study the shallow sedimentary structure south and east of southern Massachusetts and to obtain magnetic and gravity data in these areas and in the vicinity of Great South Channel and Cape Ann. The survey was conducted by the U.S. Geo­logical Survey as part of the Massachusetts Cooperative Marine Geologic Program. Seismic instruments used include a 1 Teledyne 600-joule minisparker system and a 20-in 3 airgun system. Navigational data during the cruise were obtained by the use of an Integrated Navigation System, which included the following sub­systems: Teledyne Loran-C for both range-range and hyperbofic positions; Magnovox s'atellite receiver; Sperry Mark-29 gyrocompass; and Hewlett-Packard 21 MX computer system with dual 9-track magnetic tape recording. The original records may be studied at the U.S. Geological Survey offices in Woods Hole, Mass. Copies of the records can be purchased only from the National Geophysical and Solar-Terrestrial Data Center, NOAA/EDIS/NGSDC, Code D621, 325 Broadway, Boulder CO 80303- (303-497-6338).

Open-File Report↗
USGS1981

Sidescan-sonar data collected during May 1978 from the southern New England continental shelf

Sidescan-sonar data were collected aboard R/V WESTWARD (Cruise W-39-4) during May 1978 by the U.S. Geological Survey using an Ocean Research Equipment System. Navigation in the study area was by Loran C. The 368 kilometers of survey were conducted in Block Island Sound, in Rhode Island Sound, and over the mid-Continental Shelf south of Block Island and Martha's Vineyard. Although the records are generally of good quality, variable ship speeds were caused by changes of wind and sail. Thus, care must be used in dimensional and orientation analysis of the bed-form features observed on the records. On the midshelf, three bottom types were observed: 1) smooth, featureless sea floor, 2) elongated bodies of megaripples, and 3) ground-fishing trawler marks. The distribution of the .features seems to be related to current velocity, grain-size distribution, water depth, and fishing intensity. The midshelf survey results are discussed with cruise data of R/V CAPE HENLOPEN (also collected in the spring of 1978) \ by Twichell and others. The sonographs from Block Island and Rhode Island Sounds show a pattern indicative of a till cap atop a submerged part of the coastal end moraine, as well as the megarippled and smooth sea floor. The original records may be examined in the U.S. Geological Survey offices in Woods Hole, Mass. Copies of the records can be purchased only from the National Geophysical and Solar-Terrestrial Data Center, NOAA/EDIS/NGSDC, Code D621 , 325 Broadway, Boulder, CO 80303 (303-497-6338).

Open-File Report↗
USGS1981

High-resolution seismic-reflection profiles from the Duxbury, Massachusetts, area

In August 1980, The U.S. Geological Survey conducted a seismic study (fig. 1) of the harbor and nearshore waters of Duxbury, Massachusetts, aboard the 38' research vessel R/V NEECHO. In all, 18.5 kilometers of high-resolution seismic profiles and sidescan-sonar data were obtained. The systems used included an 80-J minisparker and an EPC-32001 recorder and an EDO Western sidescan system. The navigation was by Northstar LORAN-C and by buoy-to-buoy dead reckoning within Duxbury Harbor. The original records may be viewed at the U.S. Geological Survey, Woods Hole, Massachusetts. Microfilm copies of the seismic profiles can be purchased only from the National Geophysical and Solar-Terrestrial Data Center, U.S. National Oceanic and Atmospheric Administration, NOAA/EDIS/NGSDC, 325 Broadway, Code D621, Boulder, Colorado 80303.

Massachusetts↗
USGS1996

Time-dependent Data System (TDDS); an interactive program to assemble, manage, and appraise input data and numerical output of flow/transport simulation models

A system of functional utilities and computer routines, collectively identified as the Time-Dependent Data System CI DDS), has been developed and documented by the U.S. Geological Survey. The TDDS is designed for processing time sequences of discrete, fixed-interval, time-varying geophysical data--in particular, hydrologic data. Such data include various, dependent variables and related parameters typically needed as input for execution of one-, two-, and three-dimensional hydrodynamic/transport and associated water-quality simulation models. Such data can also include time sequences of results generated by numerical simulation models. Specifically, TDDS provides the functional capabilities to process, store, retrieve, and compile data in a Time-Dependent Data Base (TDDB) in response to interactive user commands or pre-programmed directives. Thus, the TDDS, in conjunction with a companion TDDB, provides a ready means for processing, preparation, and assembly of time sequences of data for input to models; collection, categorization, and storage of simulation results from models; and intercomparison of field data and simulation results. The TDDS can be used to edit and verify prototype, time-dependent data to affirm that selected sequences of data are accurate, contiguous, and appropriate for numerical simulation modeling. It can be used to prepare time-varying data in a variety of formats, such as tabular lists, sequential files, arrays, graphical displays, as well as line-printer plots of single or multiparameter data sets. The TDDB is organized and maintained as a direct-access data base by the TDDS, thus providing simple, yet efficient, data management and access. A single, easily used, program interface that provides all access to and from a particular TDDB is available for use directly within models, other user-provided programs, and other data systems. This interface, together with each major functional utility of the TDDS, is described and documented in this report.

Water-Resources Investigations Report↗
USGS1995

Description of geophysical-log data base for boreholes and wells in and adjacent to the Albuquerque Basin, New Mexico

Digital geophysical logs for boreholes and wells in and adjacent to the Albuquerque Basin area have been entered into a data base established by the New Mexico District of the U.S. Geological Survey and documented as of September 1994. The logs were digitized from paper or mylar copies or were collected as digital data during the logging of boreholes and wells. The location of these boreholes and wells with digital geophysical logs is shown in a map. The 1,020 logs and the types of logs for the 186 sites are listed in a table.

New Mexico↗
USGS2026

Computational electromagnetic geophysics for groundwater system studies: A review on established practices and recent advances

Identifying effective solutions for locating groundwater resources and ensuring the quality of drinking water is increasingly urgent, given the challenges posed by climate change and population growth. This review investigates electromagnetic geophysical imaging techniques, in both time- and frequency-domain, that can provide valuable insights for groundwater assessment. We explore computational electromagnetic methods used to evaluate electromagnetic data and several recent hydrogeophysical case studies. As open-source frameworks for modeling electromagnetic geophysical problems become available, a broader range of researchers can interpret their data with computationally advanced software. We provide an overview of documented open-source codes for evaluating electromagnetic data and analyze various hydrological targets in relation to their electromagnetic surveying technique and the computational method applied. Furthermore, we evaluate the potential of advanced computational techniques, including three-dimensional modeling, non-deterministic inversion and machine learning, to couple geophysical with numerical groundwater modeling and apply it in groundwater system studies. Despite obstacles such as complexity and resource demands, our findings indicate that the quantification and integration of predictive uncertainties from both electromagnetic and hydrological data and simulations would significantly improve the reliability of hydrogeophysical models. This can lead to a deeper understanding of groundwater systems and improved management practices.

Journal of Hydrology↗