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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 1,297 records · Page 72Linked to original sources
USGS1989

GEOS seismograms recorded for aftershocks of the earthquakes of December 7, 1988, near Spitak, Armenia SSR, during the time period 3 January 1989 through 2 February 1988 (UTC)

The earthquakes of December 7, 1988, near Spitak, Armenia SSR, serve as another grim reminder of the serious hazard that earthquakes pose throughout the world. We extend our heartfelt sympathies to the families of the earthquake victims and intend that our cooperative scientific endeavours will help reduce losses in future earthquakes. Only through a better understanding of earthquake hazards can earthquake losses be reduced for all peoples in seismically active regions of the world. The tragic consequences of these earthquakes remind scientists and public officials alike of their urgent responsibilities to understand and mitigate the effects of earthquakes. On behalf of the U.S. Geological Survey, I would like to express appreciation to our Soviet colleagues for their kind invitation to participate in joint scientific and engineering studies. Without their cooperation and generous assistance, the conduct of these studies would not have been possible. This report provides seismologic and geologic data collected during the time period December 21, 1988, through February 2, 1989. These data are presented in their entirety to expedite analysis of the data set for inferences regarding hazard mitigation actions, applicable not only in Armenia but other regions of the world exposed to high seismic risk

Open-File Report↗
USGS2025

Integrated patterns of residence and movement create testable hypotheses about fish feeding migrations

Developing and testing alternate hypotheses about patterns, mechanisms, and consequences of movement in geographically-large, heterogeneous, natural systems can advance the scientific understanding of animal migration and benefit the conservation of most mobile species. Within organismal movement trajectories, different combinations of residence and movement are predicted from existing ecological theories (e.g. long distance migration, site fidelity, central place foraging, ideal free distribution, habitat shifts). However, testing these conceptually-based, spatially-explicit hypotheses about animal movement and migration in the field can be logistically challenging. Here our purpose is to introduce Resmo , a framework of metrics and analyses that integrate site-specific RESidence and across-site MOvements. We illustrate the ecological insights from this framework using the empirical example of coastal Striped Bass ( Morone saxatilis ) during their seasonal feeding migration. Our use of site-specific Resmo applied to empirical telemetry data enhanced the understanding of feeding behavior of migratory fish, suggested testable ecologically-meaningful hypotheses about foraging, and identified criteria on which to base the selection of future sampling locations. In summary, the Resmo approach provides a useful new direction for thinking about animal migration, animal movement, biological conservation, and future priorities for empirical field data collection related to understanding the distribution of mobile organisms.

Scientific Reports↗
USGS2003

Understanding climatic impacts, vulnerabilities, and adaptation in the United States: Building a capacity for assessment

Based on the experience of the U.S. National Assessment, we propose a program of research and analysis to advance capability for assessment of climate impacts, vulnerabilities, and adaptation options. We identify specific priorities for scientific research on the responses of ecological and socioeconomic systems to climate and other stresses; for improvement in the climatic inputs to impact assessments; and for further development of assessment methods to improve their practical utility to decision-makers. Finally, we propose a new institutional model for assessment, based principally on regional efforts that integrate observations, research, data, applications, and assessment on climate and linked environmental-change issues. The proposed program will require effective collaboration between scientists, resource managers, and other stakeholders, all of whose expertise is needed to define and prioritize key regional issues, characterize relevant uncertainties, and assess potential responses. While both scientifically and organizationally challenging, such an integrated program holds the best promise of advancing our capacity to manage resources and the economy adaptively under a changing climate.

Climatic Change↗
USGS2014

Estimates of groundwater recharge rates and sources in the East Mountain area, Eastern Bernalillo County, New Mexico, 2005-12

The U.S. Geological Survey, in cooperation with the Bernalillo County Public Works Division, has conducted a monitoring program in the East Mountain area of eastern Bernalillo County, New Mexico, since 2000 to better define the hydrogeologic characteristics of the East Mountain area and to provide scientific information that will assist in the sustainable management of water resources. This report presents estimates of groundwater recharge to the aquifers that supply water to a network of springs that discharged within the East Mountain area of eastern Bernalillo County during 2005–12. Chloride concentration, the mass ratio of chloride to bromide, and the stable isotope ratios of hydrogen and oxygen were used to estimate annual groundwater recharge rates and to identify the sources and timing of recharge to the aquifers in the East Mountain area. Groundwater recharge rates were estimated by using a chloride mass-balance (CMB) method applied to data from selected springs located in the study area. Eleven springs and four downgradient monitoring wells were sampled for this study. On the basis of chloride concentrations and the mass ratio of chloride to bromide, eight of the eleven sampled springs are considered representative of dilute groundwater recharged by meteoric water in the Sandia Mountains. Eight of the eleven springs sampled as part of this investigation are considered representative of dilute groundwater not influenced by nonmeteoric chloride sources on the basis of analysis of chloride concentrations and the mass ratio of chloride to bromide. Chloride concentrations at three of the sampled springs were likely affected by nonmeteoric chloride sources. Results of CMB calculations for the eight springs with Cl:Br ratios and chloride concentrations within the range of dilute groundwater (not influenced by nonmeteoric chloride sources) indicated that between about 5.5 and 23 percent of annual precipitation recharges the groundwater system. The variation in estimated recharge rates indicated that the mechanisms for recharge and groundwater movement in the East Mountain area are complex and that factors such as climate variability, the extent and interconnection of structural features such as faults and fractures, and potential solution enhancement of the aquifers all play important roles in the rates and timing of recharge. Stable isotope data from springs and snowpacks sampled in the East Mountain area were compared with local, regional, and global meteoric water lines and were analyzed along with values representing the stable isotope composition of winter precipitation and summer monsoonal rains. Results of the stable isotope analysis from springs in this study suggested that winter precipitation is the primary source of groundwater recharge to the aquifers supplying the springs, but there is a component of more isotopically enriched precipitation being recharged as well, likely from summer monsoonal rains. Specific conductance, groundwater-level hydrographs, snowpack chemistry, and snow-water equivalent data were used to inform the analyses and corroborate the findings of the CMB and stable isotope results.

New Mexico↗
USGS2012

Creation of digital contours that approach the characteristics of cartographic contours

The capability to easily create digital contours using commercial off-the-shelf (COTS) software has existed for decades. Out-of-the-box raw contours are suitable for many scientific applications without pre- or post-processing; however, cartographic applications typically require additional improvements. For example, raw contours generally require smoothing before placement on a map. Cartographic contours must also conform to certain spatial/logical rules; for example, contours may not cross waterbodies. The objective was to create contours that match as closely as possible the cartographic contours produced by manual methods on the 1:24,000-scale, 7.5-minute Topographic Map series. This report outlines the basic approach, describes a variety of problems that were encountered, and discusses solutions. Many of the challenges described herein were the result of imperfect input raster elevation data and the requirement to have the contours integrated with hydrographic features from the National Hydrography Dataset (NHD).

Scientific Investigations Report↗
USGS2014

Wave-driven sediment mobilization on a storm-controlled continental shelf (Northwest Iberia)

Seafloor sediment mobilization on the inner Northwest Iberian continental shelf is caused largely by ocean surface waves. The temporal and spatial variability in the wave height, wave period, and wave direction has a profound effect on local sediment mobilization, leading to distinct sediment mobilization scenarios. Six grain-size specific sediment mobilization scenarios, representing seasonal average and storm conditions, were simulated with a physics-based numerical model. Model inputs included meteorological and oceanographic data in conjunction with seafloor grain-size and the shelf bathymetric data. The results show distinct seasonal variations, most importantly in wave height, leading to sediment mobilization, specifically on the inner shelf shallower than 30 m water depth where up to 49% of the shelf area is mobilized. Medium to severe storm events are modeled to mobilize up to 89% of the shelf area above 150 m water depth. The frequency of each of these seasonal and storm-related sediment mobilization scenarios is addressed using a decade of meteorological and oceanographic data. The temporal and spatial patterns of the modeled sediment mobilization scenarios are discussed in the context of existing geological and environmental processes and conditions to assist scientific, industrial and environmental efforts that are directly affected by sediment mobilization. Examples, where sediment mobilization plays a vital role, include seafloor nutrient advection, recurrent arrival of oil from oil-spill-laden seafloor sediment, and bottom trawling impacts.

Journal of Marine Systems↗
USGS2014

Discrete-storm water-table fluctuation method to estimate episodic recharge.

We have developed a method to identify and quantify recharge episodes, along with their associated infiltration-related inputs, by a consistent, systematic procedure. Our algorithm partitions a time series of water levels into discrete recharge episodes and intervals of no episodic recharge. It correlates each recharge episode with a specific interval of rainfall, so storm characteristics such as intensity and duration can be associated with the amount of recharge that results. To be useful in humid climates, the algorithm evaluates the separability of events, so that those whose recharge cannot be associated with a single storm can be appropriately lumped together. Elements of this method that are subject to subjectivity in the application of hydrologic judgment are values of lag time, fluctuation tolerance, and master recession parameters. Because these are determined once for a given site, they do not contribute subjective influences affecting episode-to-episode comparisons. By centralizing the elements requiring scientific judgment, our method facilitates such comparisons by keeping the most subjective elements openly apparent, making it easy to maintain consistency. If applied to a period of data long enough to include recharge episodes with broadly diverse characteristics, the method has value for predicting how climatic alterations in the distribution of storm intensities and seasonal duration may affect recharge.

Groundwater↗
USGS2009

The ecological limits of hydrologic alteration (ELOHA): A new framework for developing regional environmental flow standards

The flow regime is a primary determinant of the structure and function of aquatic and riparian ecosystems for streams and rivers. Hydrologic alteration has impaired riverine ecosystems on a global scale, and the pace and intensity of human development greatly exceeds the ability of scientists to assess the effects on a river-by-river basis. Current scientific understanding of hydrologic controls on riverine ecosystems and experience gained from individual river studies support development of environmental flow standards at the regional scale. 2. This paper presents a consensus view from a group of international scientists on a new framework for assessing environmental flow needs for many streams and rivers simultaneously to foster development and implementation of environmental flow standards at the regional scale. This framework, the ecological limits of hydrologic alteration (ELOHA), is a synthesis of a number of existing hydrologic techniques and environmental flow methods that are currently being used to various degrees and that can support comprehensive regional flow management. The flexible approach allows scientists, water-resource managers and stakeholders to analyse and synthesise available scientific information into ecologically based and socially acceptable goals and standards for management of environmental flows. 3. The ELOHA framework includes the synthesis of existing hydrologic and ecological databases from many rivers within a user-defined region to develop scientifically defensible and empirically testable relationships between flow alteration and ecological responses. These relationships serve as the basis for the societally driven process of developing regional flow standards. This is to be achieved by first using hydrologic modelling to build a 'hydrologic foundation' of baseline and current hydrographs for stream and river segments throughout the region. Second, using a set of ecologically relevant flow variables, river segments within the region are classified into a few distinctive flow regime types that are expected to have different ecological characteristics. These river types can be further subclassified according to important geomorphic features that define hydraulic habitat features. Third, the deviation of current-condition flows from baseline-condition flow is determined. Fourth, flow alteration-ecological response relationships are developed for each river type, based on a combination of existing hydroecological literature, expert knowledge and field studies across gradients of hydrologic alteration. 4. Scientific uncertainty will exist in the flow alteration-ecological response relationships, in part because of the confounding of hydrologic alteration with other important environmental determinants of river ecosystem condition (e.g. temperature). Application of the ELOHA framework should therefore occur in a consensus context where stakeholders and decision-makers explicitly evaluate acceptable risk as a balance between the perceived value of the ecological goals, the economic costs involved and the scientific uncertainties in functional relationships between ecological responses and flow alteration. 5. The ELOHA framework also should proceed in an adaptive management context, where collection of monitoring data or targeted field sampling data allows for testing of the proposed flow alteration-ecological response relationships. This empirical validation process allows for a fine-tuning of environmental flow management targets. The ELOHA framework can be used both to guide basic research in hydroecology and to further implementation of more comprehensive environmental flow management of freshwater sustainability on a global scale. ?? 2009 Blackwell Publishing Ltd.

Freshwater Biology↗
USGS2004

The elusive baseline of marine disease: Are diseases in ocean ecosystems increasing?

Disease outbreaks alter the structure and function of marine ecosystems, directly affecting vertebrates (mammals, turtles, fish), invertebrates (corals, crustaceans, echinoderms), and plants (seagrasses). Previous studies suggest a recent increase in marine disease. However, lack of baseline data in most communities prevents a direct test of this hypothesis. We developed a proxy to evaluate a prediction of the increasing disease hypothesis: the proportion of scientific publications reporting disease increased in recent decades. This represents, to our knowledge, the first quantitative use of normalized trends in the literature to investigate an ecological hypothesis. We searched a literature database for reports of parasites and disease (hereafter “disease”) in nine marine taxonomic groups from 1970 to 2001. Reports, normalized for research effort, increased in turtles, corals, mammals, urchins, and molluscs. No significant trends were detected for seagrasses, decapods, or sharks/rays (though disease occurred in these groups). Counter to the prediction, disease reports decreased in fishes. Formulating effective resource management policy requires understanding the basis and timing of marine disease events. Why disease outbreaks increased in some groups but not in others should be a priority for future investigation. The increase in several groups lends urgency to understanding disease dynamics, particularly since few viable options currently exist to mitigate disease in the oceans.

PLoS Biology↗
USGS2003

The National Map: from geography to mapping and back again

When the means of production for national base mapping were capital intensive, required large production facilities, and had ill-defined markets, Federal Government mapping agencies were the primary providers of the spatial data needed for economic development, environmental management, and national defense. With desktop geographic information systems now ubiquitous, source data available as a commodity from private industry, and the realization that many complex problems faced by society need far more and different kinds of spatial data for their solutions, national mapping organizations must realign their business strategies to meet growing demand and anticipate the needs of a rapidly changing geographic information environment. The National Map of the United States builds on a sound historic foundation of describing and monitoring the land surface and adds a focused effort to produce improved understanding, modeling, and prediction of land-surface change. These added dimensions bring to bear a broader spectrum of geographic science to address extant and emerging issues. Within the overarching construct of The National Map, the U.S. Geological Survey (USGS) is making a transition from data collector to guarantor of national data completeness; from producing paper maps to supporting an online, seamless, integrated database; and from simply describing the Nation’s landscape to linking these descriptions with increased scientific understanding. Implementing the full spectrum of geographic science addresses a myriad of public policy issues, including land and natural resource management, recreation, urban growth, human health, and emergency planning, response, and recovery. Neither these issues nor the science and technologies needed to deal with them are static. A robust research agenda is needed to understand these changes and realize The National Map vision. Initial successes have been achieved. These accomplishments demonstrate the utility of The National Map to the Nation and give confidence in evolving its future applications.

Photogrammetric Engineering and Remote Sensing↗
USGS2011

Development of industrial minerals in Colorado

Technology and engineering have helped make mining safer and cleaner for both humans and the environment. Inevitably, mineral development entails costs as well as benefits. Developing a mine is an environmental, engineering, and planning challenge that must conform to many Federal, State, and local regulations. Community collaboration, creative design, and best management practices of sustainability and biodiversity can be positive indicators for the mining industry. A better understanding of aesthetics, culture, economics, geology, climate, vegetation and wildlife, topography, historical significance, and regional land planning is important in resolving land-use issues and managing mineral resources wisely. Ultimately, the consuming public makes choices about product use (including water, food, highways, housing, and thousands of other items) that influence operations of the mineral industry. Land planners, resource managers, earth scientists, designers, and public groups have a responsibility to consider sound scientific information, society's needs, and community appeals in making smart decisions concerning resource use and how complex landscapes should change. An effort to provide comprehensive geosciences data for land management agencies in central Colorado was undertaken in 2003 by scientists of the U.S. Geological Survey and the Colorado Geological Survey. This effort, the Central Colorado Assessment Project, addressed a variety of land-use issues: an understanding of the availability of industrial and metallic rocks and minerals, the geochemical and environmental effects of historic mining activity on surface water and groundwater, and the geologic controls on the availability and quality of groundwater. The USDA Forest Service and other land management agencies have the opportunity to contribute to the sustainable management of natural aggregate and other mineral resources through the identification and selective development of mineral resources and the reclamation of mines on lands that they administer. The information in this Circular will help them carry out that task.

Colorado↗
USGS1997

U.S. Geological Survey Studies of Energy Resources in Sub-Saharan Africa

The U.S. Government and the American public need access to information on energy resources in sub-Saharan Africa. Sub-Saharan Africa (mostly Nigeria) produces 5 percent of the world's oil, while supplying the United States with 15 percent of our imports (Energy Information Administration). In the next 10 years, sub-Saharan oil and gas will become increasingly more important to the export market. New discoveries in offshore provinces of West Africa ensure a bright future for the region. Projections indicate that increased oil production in sub-Saharan Africa will far outpace the growth of intraregional consumption, providing greater quantities of oil for export (Forman, 1996). Also, West Africa, although a marginal supplier of liquefied natural gas (LNG) today, will become an important LNG source to the international market by the year 2000 (Oil & Gas Journal, 1996). The United States needs up-to-date information about petroleum resources and the energy balance within the region to predict the future role of sub-Saharan Africa as a major oil and gas exporter. The data required to generate the needed information are often disseminated in archives of oil companies and African geologic surveys, or in obscure publications. For these reasons, the U.S. Geological Survey is collecting data on sub-Saharan energy and constructing a regional energy bibliography. The team of geoscientists will assure that this information is available quickly and from a scientifically based, objective view point.

Fact Sheet↗
USGS1999

National Water-Quality Assessment Program: Great Salt Lake basins study unit

The Great Salt Lake Basins NAWQA study will increase the scientific understanding of the factors that influence surface- and ground-water quality. This information will benefit water-resources managers that need, but often lack, the data required to implement effective water-quality management actions and evaluate long-term changes in water quality.

Idaho, Utah, Wyoming↗
USGS2013

Digital data from the Great Sand Dunes airborne gravity gradient survey, south-central Colorado

This report contains digital data and supporting explanatory files describing data types, data formats, and survey procedures for a high-resolution airborne gravity gradient (AGG) survey at Great Sand Dunes National Park, Alamosa and Saguache Counties, south-central Colorado. In the San Luis Valley, the Great Sand Dunes survey covers a large part of Great Sand Dunes National Park and Preserve. The data described were collected from a high-resolution AGG survey flown in February 2012, by Fugro Airborne Surveys Corp., on contract to the U.S. Geological Survey. Scientific objectives of the AGG survey are to investigate the subsurface structural framework that may influence groundwater hydrology and seismic hazards, and to investigate AGG methods and resolution using different flight specifications. Funding was provided by an airborne geophysics training program of the U.S. Department of Defense's Task Force for Business & Stability Operations.

Colorado↗
USGS2005

Results of land cover change detection analysis in and around Cordillera Azul National Park, Peru

The first product of the Optimizing Design and Management of Protected Areas for Conservation Project is a land cover change detection analysis based on Landsat thematic mapper (TM) and enhanced thematic mapper plus (ETM+) imagery collected at intervals between 1989 and 2002. The goal of this analysis was to quantify and analyze patterns of forest clearing, land conversion, and other disturbances in and around the Cordillera Azul National Park in Peru. After removing clouds and cloud shadows from the imagery using a series of automatic and manual processes, a Tasseled Cap Transformation was used to detect pixels of high reflectance, which were classified as bare ground and areas of likely forest clearing. Results showed a slow but steady increase in cleared ground prior to 1999 and a rapid and increasing conversion rate after that time. The highest concentrations of clearings have spread upward from the western border of the study area on the Huallaga River. To date, most disturbances have taken place in the buffer zone around the park, not within it, but the data show dense clearings occurring closer to the park border each year.

Scientific Investigations Map↗
USGS2008

Potentiometric Surface in the Sparta-Memphis Aquifer of the Mississippi Embayment, Spring 2007

The most widely used aquifer for industry and public supply in the Mississippi embayment in Arkansas, Louisiana, Mississippi, and Tennessee is the Sparta-Memphis aquifer. Decades of pumping from the Sparta-Memphis aquifer have affected ground-water levels throughout the Mississippi embayment. Regional assessments of water-level data from the aquifer are important to document regional water-level conditions and to develop a broad view of the effects of ground-water development and management on the sustainability and availability of the region's water supply. This information is useful to identify areas of water-level declines, identify cumulative areal declines that may cross State boundaries, evaluate the effectiveness of ground-water management strategies practiced in different States, and identify areas with substantial data gaps that may preclude effective management of ground-water resources. A ground-water flow model of the northern Mississippi embayment is being developed by the Mississippi Embayment Regional Aquifer Study (MERAS) to aid in answering questions about ground-water availability and sustainability. The MERAS study area covers parts of eight states including Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee and covers approximately 70,000 square miles. The U.S. Geological Survey (USGS) and the Mississippi Department of Environmental Quality Office of Land and Water Resources measured water levels in wells completed in the Sparta-Memphis aquifer in the spring of 2007 to assist in the MERAS model calibration and to document regional water-level conditions. Measurements by the USGS and the Mississippi Department of Environmental Quality Office of Land and Water Resources were done in cooperation with the Arkansas Natural Resources Commission; the Arkansas Geological Survey; Memphis Light, Gas and Water; Shelby County, Tennessee; and the city of Germantown, Tennessee. In 2005, total water use from the Sparta-Memphis aquifer in the Mississippi embayment was about 540 million gallons per day (Mgal/d). Water use from the Sparta-Memphis aquifer was about 170 Mgal/d in Arkansas, about 68 Mgal/d in Louisiana, about 97 Mgal/d in Mississippi, and about 205 Mgal/d in Tennessee. The author acknowledges, with great appreciation, the efforts of the personnel in the U.S. Geological Survey Water Science Centers of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee, and the Mississippi Department of Environmental Quality Office of Land and Water Resources that participated in the planning, water-level measurement, data evaluation, and review of the potentiometric-surface map. Without the contribution of data and the technical assistance of their staffs, this report would not have been completed.

Scientific Investigations Map↗
USGS2014

Vegetation types in coastal Louisiana in 2013

During the summer of 2013, the U.S. Geological Survey, Louisiana State University, University of Louisiana at Lafayette, and the Louisiana Department of Wildlife and Fisheries Coastal and Nongame Resources Division jointly completed an aerial survey to collect data on 2013 vegetation types in coastal Louisiana. Plant species were listed and their abundance classified. On the basis of species composition and abundance, each marsh sampling station was assigned a marsh type: fresh, intermediate, brackish, or saline (saltwater) marsh. The current map presents the data collected in this effort.

Louisiana↗