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At least 451 records · Page 25Linked to original sources
USGS2018

The Central African Republic Diamond Database—A geodatabase of archival diamond occurrences and areas of recent artisanal and small-scale diamond mining

The alluvial diamond deposits of the Central African Republic (CAR) are mined almost exclusively by way of informal artisanal and small-scale mining (ASM) methods. ASM sites range in diameter from a few meters to 30 meters or more, and are typically excavated by crews of diggers using hand tools, sieves, and jigs. CAR’s reported annual production has ranged from 300,000 to 470,000 carats over the past decade. This production is significant for CAR because it accounts for a large portion of the country’s export income and employs an estimated 60,000 to 90,000 miners nationally. Diamond production has also been linked to the violent conflict and political instability which have plagued the country for decades. The most recent conflict began in 2012 and resulted in an international embargo on the export of rough diamonds from CAR. This embargo was followed by a ceasefire and a return of peace in certain zones of the country in 2015; however, political and economic instability continues to afflict many areas of the country. International efforts to restore peace in CAR have included United Nations support as well as international technical assistance in tracking, assessing, and monitoring diamond production. In 2015, the Kimberley Process (KP) developed an operational framework allowing for legitimate exports from five subprefectures in CAR that were deemed to be compliant with KP internal controls and which were also considered to be free from systematic violence or control of armed groups. The goal of this study was to address information gaps regarding the location and extent of diamond occurrences and mining activity through the integration of geologic research with remote sensing, geographic information systems analysis, and fieldwork. Effective and efficient monitoring of diamond mining activity using satellite imagery requires detailed understanding of the geographic distribution of diamond sources and mining activities. A two-phase methodology was developed to address the knowledge gaps. The first phase consisted of the creation of a comprehensive geospatial catalogue of diamond mining and occurrence locations from archival records such as historical maps, mining reports, academic publications, and field data. Building upon this locational database, the second phase consisted of the creation of a geospatial dataset cataloguing current mining activity locations through manual interpretation of recently acquired satellite imagery. The accuracy of this second geospatial dataset was then assessed using field observations made between 2016 and 2017 by the U.S. Agency for International Development’s Property Rights and Artisanal Diamond Development II project. This report presents a two-part geodatabase: part 1 contains the locations of diamond mine sites and occurrences from archival sources, and part 2 indicates areas of current or recent mining activity. This geodatabase is unique in its temporal and spatial extent and may be used to analyze the geographic distribution of CAR’s known diamond resources, to assess the effect of recent violent conflicts and KP actions on diamond produc-tion, to provide decision makers with information regarding small-scale diamond mining, and to improve the monitoring of mining in regions of the country prone to conflict.

Open-File Report↗
USGS2023

Cruise Report for NOAA Ship Nancy Foster Cruise NF-22-06

Between 9 August and 1 September, 2022, the Mesophotic and Deep Benthic (MDBC) Habitat Assessment and Evaluation (HAE) and Mapping, Ground-truthing, and Predictive Habitat Modeling (MGM) projects implemented remotely operated vehicle (ROV) dives, multibeam surveys, and conductivity, temperature, depth (CTD) operations at deep-sea sites in the northern Gulf of Mexico. The primary sites selected are a region of known deep-sea coral habitats, including Deepwater Horizon (DWH) injured and reference sites at depths of 1,100–2,000 m. The cruise includes objectives from MGM and HAE projects. Habitat characterization and analysis of biological samples collected with ROV Odysseus maintain long-term data flows and fill critical data gaps on the biology and ecology at impacted and reference sites, assess potential ongoing impacts from threats, refine predictive habitat models, help target locations for direct restoration and protection, and determine a baseline for health and condition. Multibeam echosounder data can help document the broadscale abundance and distribution of MDBC, characterize benthic habitats, and provide information that can help guide future ROV surveys.

DWH MDBC Cruise Report↗
USGS1984

Ground-water models as a management tool in Florida

Highly sophisticated computer models provide powerful tools for analyzing historic data and for simulating future water levels, water movement, and water chemistry under stressed conditions throughout the ground-water system in Florida. Models that simulate the movement of heat and subsidence of land in response to aquifer pumping also have potential for application to hydrologic problems in the State. Florida, with 20 ground-water modeling studies reported since 1972, has applied computer modeling techniques to a variety of water-resources problems. Models in Florida generally have been used to provide insight to problems of water supply, contamination, and impact on the environment. The model applications range from site-specific studies, such as estimating contamination by wastewater injection at St. Petersburg, to a regional model of the entire State that may be used to assess broad-scale environmental impact of water-resources development. Recently, groundwater models have been used as management tools by the State regulatory authority to permit or deny development of water resources. As modeling precision, knowledge, and confidence increase, the use of ground-water models will shift more and more toward regulation of development and enforcement of environmental laws. (USGS)

Water-Resources Investigations Report↗
USGS2014

Downscaled climate projections for the Southeast United States: evaluation and use for ecological applications

Climate change is likely to have many effects on natural ecosystems in the Southeast U.S. The National Climate Assessment Southeast Technical Report (SETR) indicates that natural ecosystems in the Southeast are likely to be affected by warming temperatures, ocean acidification, sea-level rise, and changes in rainfall and evapotranspiration. To better assess these how climate changes could affect multiple sectors, including ecosystems, climatologists have created several downscaled climate projections (or downscaled datasets) that contain information from the global climate models (GCMs) translated to regional or local scales. The process of creating these downscaled datasets, known as downscaling, can be carried out using a broad range of statistical or numerical modeling techniques. The rapid proliferation of techniques that can be used for downscaling and the number of downscaled datasets produced in recent years present many challenges for scientists and decisionmakers in assessing the impact or vulnerability of a given species or ecosystem to climate change. Given the number of available downscaled datasets, how do these model outputs compare to each other? Which variables are available, and are certain downscaled datasets more appropriate for assessing vulnerability of a particular species? Given the desire to use these datasets for impact and vulnerability assessments and the lack of comparison between these datasets, the goal of this report is to synthesize the information available in these downscaled datasets and provide guidance to scientists and natural resource managers with specific interests in ecological modeling and conservation planning related to climate change in the Southeast U.S. This report enables the Southeast Climate Science Center (SECSC) to address an important strategic goal of providing scientific information and guidance that will enable resource managers and other participants in Landscape Conservation Cooperatives to make science-based climate change adaptation decisions.

Open-File Report↗
USGS2006

Land-Cover and Imperviousness Data for Regional Areas near Denver, Colorado; Dallas-Fort Worth, Texas; and Milwaukee-Green Bay, Wisconsin - 2001

This report describes the processing and results of land-cover and impervious surface derivation for parts of three metropolitan areas being studied as part of the U.S. Geological Survey's (USGS) National Water-Quality Assessment (NAWQA) Program Effects of Urbanization on Stream Ecosystems (EUSE). The data were derived primarily from Landsat-7 Enhanced Thematic Mapper Plus (ETM+) satellite imagery from the period 1999-2002, and are provided as 30-meter resolution raster datasets. Data were produced to a standard consistent with data being produced as part of the USGS National Land Cover Database 2001 (NLCD01) Program, and were derived in cooperation with, and assistance from, NLCD01 personnel. The data were intended as surrogates for NLCD01 data because of the EUSE Program's time-critical need for updated land-cover for parts of the United States that would not be available in time from the NLCD01 Program. Six datasets are described in this report: separate land-cover (15-class categorical data) and imperviousness (0-100 percent continuous data) raster datasets for parts of the general Denver, Colorado area (South Platte River Basin), Dallas-Fort Worth, Texas area (Trinity River Basin), and Milwaukee-Green Bay, Wisconsin area (Western Lake Michigan Drainages).

Data Series↗
USGS1977

Shelled benthic fauna of the eastern Chukchi Sea

The purposes of this study were to identify the benthic shelled infauna and epifauna of the eastern Chukchi Sea, compile species lists and distribution maps, determine recurrent groups of species (communities), and examine the environmental parameters that may control the distribution of the faunal groups. The study was partly supported by the Bureau of Land Management through an interagency agreement with the National Oceanic and Atmospheric Administration, under which a multi-year program responding to the needs of petroleum development of the Alaskan continental shelf is managed by the Outer Continental Shelf Environmental Assessment Program (OCSEAP) Office. The objective of this study is to provide an assessment of the biological patterns of the region as related to petroleum development. Future offshore oil leases proposed by the State of Alaska and the Federal Government require a biological data base from which impact statements can be derived. Samples used in this report were collected by the U.S. Geological Survey in August 1974 from the U.S. Coast Guard Cutter Burton Island under the direction of Arthur Grantz. Sampling was conducted using van Veen grabs, gravity cores, dart cores, and bottom dredges. Only the van Veen grabs contained material useful for this study. At present 103 samples containing 90 species have been examined.

Alaska↗
USGS2018

2018 update to the U.S. Geological Survey national volcanic threat assessment

When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U.S. Geological Survey and its partners. This update of the volcano threat assessment of Ewert and others (2005) considers new research in order to determine which volcanic systems should be added or removed from the list of potentially active volcanoes, updates the scoring of active volcanoes, and updates the 24-factor hazard and exposure matrix used to create the threat ranking. The threat assessment places volcanoes into five threat categories: very low, low, moderate, high, and very high. Within all five threat categories there are changes in relative rankings of volcanoes, and in a few cases, volcanoes moved between categories owing to changes in our understanding of their hazard, unrest, and exposure factors. Scorings of hazard factors were updated for some volcanoes where new research has identified Holocene eruptive activity or clarified our understanding of Holocene eruptive history and the occurrence of particular hazards such as tephra fall or pyroclastic density currents. The most numerous scoring changes made in the threat matrix since 2005 have been made among the hazard factors, particularly those accounting for observed eruptive activity or unrest. The very low threat category underwent the greatest amount of change, dropping from 32 to 21 volcanoes, owing to better knowledge of the eruptive histories of those volcanoes. The list of 18 very high threat volcanoes determined by Ewert and others (2005) remains the same; 11 of the 18 volcanoes are located in Washington, Oregon, or California, where explosive and often snow- and ice-covered edifices can project hazards long distances to densely populated and highly developed areas. Five of the 18 very high threat volcanoes are in Alaska near important population centers, economic infrastructure, or below busy air traffic corridors. The remaining two very high threat volcanoes are on the Island of Hawaiʻi, where densely populated and highly developed areas now exist on the flanks of highly active volcanoes. The high- and moderate-threat categories are dominated by Alaskan volcanoes. In these categories the generally more active and more explosive volcanoes in Alaska can have a substantial effect on national and international aviation, and large eruptions from any of the moderate- to very-high-threat volcanoes could cause regional or national-scale disasters. This revised threat assessment includes 18 very high threat, 39 high threat, 49 moderate threat, 34 low threat, and 21 very low threat volcanoes. The total of 161 volcanoes is a decrease of 8 from the total reported by Ewert and others (2005).

Scientific Investigations Report↗
USGS2005

Inventory of the mosses, liverworts, and lichens of Olympic National Park, Washington- Species list

The identification of non-vascular cryptogam species (lichens, mosses, liverworts, and hornworts) is especially challenging because of their small size, their often microscopic or chemical distinguishing features, and their enormous diversity. Consequently, they are a poorly known component of Olympic National Park, despite their ecological and aesthetic importance. This project is the first attempt at a systematic, comprehensive survey of non-vascular cryptogams in the Park and presents the current species list with descriptions of the substrate and vascular vegetation type where they were observed. The authors strove to collect from as many park environments as feasible, and distributed collections along important environmental gradients in different regions of the park using vascular vegetation as an environmental indicator. They also collected opportunistically when interesting habitats or microhabitats were encountered. Finally, the authors updated the nomenclature in the Park’s previous collection of nonvascular plants. This study identified approximately 13,200 bryophyte and lichen species, adding approximately 425 new species to the Olympic National Park Herbarium. These data, combined with select literature reports and personal data from Martin and Karen Hutten, added more than 350 species to the previously documented Olympic Peninsula lichen and bryophyte list. The authors discuss the list in a local, regional, and global context of rarity, as well as cryptogam conservation and further work needed in Olympic National Park. The improved inventory of Olympic National Park cryptogams represented by this project enables Olympic National Park to protect populations of rare and sensitive species, assess the damage caused by illegal harvest, and contribute information to the Bureau of Land Management and U.S. Forest Service Sensitive Species Programs.

Scientific Investigations Report↗
USGS2014

Assessing inundation hazards to nuclear powerplant sites using geologically extended histories of riverine floods, tsunamis, and storm surges

Most nuclear powerplants in the United States are near rivers, large lakes, or oceans. As evident from the Fukushima Daiichi, Japan, disaster of 2011, these water bodies pose inundation threats. Geologic records can extend knowledge of rare hazards from flooding, storm surges, and tsunamis. This knowledge can aid in assessing the safety of critical structures such as dams and energy plants, for which even remotely possible hazards are pertinent. Quantitative analysis of inundation from geologic records perhaps is most developed for and applied to riverine flood hazards, but because of recent natural disasters, geologic investigations also are now used widely for understanding tsunami hazards and coastal storm surges. Layered sedimentary deposits commonly give the most complete geologic record of large floods, storm surges, and tsunamis. Sedimentary layers may be preserved for hundreds or thousands of years in suitable depositional environments, thereby providing an archive of rare, high-magnitude events. All inundation hazards discussed in this report—riverine floods, tsunamis, and storm surges—have had long records extracted from sedimentary sequences, many specifically for hazard assessment. Geologic records commonly are imprecise, so most hazard assessments benefit from evaluation of many sites and rigorous uncertainty assessment. Despite uncertainties, geologic records commonly can improve knowledge of the types and magnitudes of hazards threatening specific sites or regions. New statistical tools and approaches can efficiently incorporate geologic information into frequency assessments. These tools are most developed for riverine flood hazards, but are to some degree transferable to other episodic natural phenomena such as tsunamis and storm surges. Even with these efficient statistical approaches for examining geologic records, systematic landscape changes may reduce the applicability of retrospective assessments. These non-stationarity issues (such as climate change, sea‑level rise, land-use, dams and flow regulation) may all affect the validity of using past experience—no matter how complete the record—to assess future likelihoods. These issues require site-specific consideration for nearly all hazard assessments drawn from geologic evidence. A screening of the 104 nuclear powerplants in the United States licensed by the Nuclear Regulatory Commission (at 64 sites) indicates several sites for which paleoflood studies likely would provide additional flood-frequency information. Two sites—Duane Arnold, Iowa, on the Cedar River; and David-Besse, Ohio, on the Toussaint River—have geologic conditions suitable for creating and preserving stratigraphic records of flooding and few upstream dams that may complicate flood-frequency analysis. One site—Crystal River, Florida1, on the Withlacoochee River and only 4 kilometers from the coast—has high potential as a candidate for assessing riverine and marine inundation hazards. Several sites on the Mississippi River have high geologic potential, but upstream dams almost certainly now regulate peak flows. Nevertheless, studies on the Mississippi River to evaluate long-term flood frequency may provide results applicable to a wide spectrum of regional hazard issues. Several sites in the southeastern United States have high geologic potential, and studies at these sites also may be helpful in evaluating hazards from outburst floods from landslide dams (river blockages formed by mass movements), which may be a regional hazard. For all these sites, closer investigation and field reconnaissance would be needed to confirm suitable deposits and settings for a complete paleoflood analysis. Similar screenings may help identify high-potential sites for geologic investigations of tsunami and storm-surge hazards.

Scientific Investigations Report↗
USGS2006

Atlas of climatic controls of wildfire in the western United States

Wildfire behavior depends on several factors including ecologic characteristics, near-term and antecedent climatic conditions,fuel availability and moisture level, weather, and sources of ignition (lightning or human). The variability and interplay of these factors over many spatial and temporal scales present an ongoing challenge to our ability to forecast a given wildfire season. Here we focus on one aspect of wildfire in the western US through a retrospective analysis of wildfire (starts and area burned) and climate over monthly time scales. We consider prefire conditions up to a year preceding fire outbreaks. For our analysis, we used daily and monthly wildfire records and a combination of observed and model-simulated atmospheric and surface climate data. The focus of this report is on monthly wildfire and climate for the period 1980-2000. Although a longer fire record is desirable, the 21-year record is the longest currently available and it is sufficient for the purpose of a first-order regional analysis. We present the main results in the form of a wildfire-climate atlas for 8 subregions of the West that can be used by resource managers to assess current wildfire conditions relative to high, normal, and low fire years in the historical record. Our results clearly demonstrate the link between wildfire conditions and a small set of climatic variables, and our methodology is a framework for providing near-real-time assessments of current wildfire conditions in the West.

Scientific Investigations Report↗
USGS2016

Report from the workshop on climate downscaling and its application in high Hawaiian Islands, September 16–17, 2015

In the subtropical and tropical Pacific islands, changing climate is predicted to influence precipitation and freshwater availability, and thus is predicted to impact ecosystems goods and services available to ecosystems and human communities. The small size of high Hawaiian Islands, plus their complex microlandscapes, require downscaling of global climate models to provide future projections of greater skill and spatial resolution. Two different climate modeling approaches (physics-based dynamical downscaling and statistics-based downscaling) have produced dissimilar projections. Because of these disparities, natural resource managers and decision makers have low confidence in using the modeling results and are therefore are unwilling to include climate-related projections in their decisions. In September 2015, the Pacific Islands Climate Science Center (PICSC), the Pacific Islands Climate Change Cooperative (PICCC), and the Pacific Regional Integrated Sciences and Assessments (Pacific RISA) program convened a 2-day facilitated workshop in which the two modeling teams, plus key model users and resource managers, were brought together for a comparison of the two approaches, culminating with a discussion of how to provide predictions that are useable by resource managers. The proceedings, discussions, and outcomes of this Workshop are summarized in this Open-File Report.

Hawaii↗
USGS2025

Climate change and future water availability in the United States

The steady rise in global temperature as a result of human activity is causing changes in Earth’s water cycle. The balance of water stored within and moving between vapor, liquid, and frozen states in the water cycle is shifting, with consequences for water availability that include increases in drought, fire weather, flooding, and heavy precipitation, as well as cryosphere decline and sea-level rise. In this chapter of the U.S. Geological Survey Integrated Water Availability Assessment—2010–20, we provide an overview of climate-change observations and projections from Earth-system model simulations that relate to future water availability, from global and national climate assessments and from the published literature. Effects of climate change on primary water-cycle components are discussed in context of how global-scale hydroclimate drivers influence regional processes within the United States. Understanding the major climate drivers impacting the water cycle is crucial to predicting future changes in water availability and developing adaptation strategies to ensure human and ecosystem water supplies. First, we provide background information on the water cycle, the climate-model ensemble simulations developed to produce projections based on warming scenarios, and attribution and certainty levels. Tipping points, self-reinforcing feedbacks, cascading effects, and compound extremes are introduced. The framework of climatic impact drivers (CIDs) outlined in the Intergovernmental Panel on Climate Change Sixth Assessment Report (IPCC AR6) is used to show primary drivers of physical change to the water cycle and to understand and predict changes in future water availability. Specific climate-change related observations and projections are discussed for water cycle components of precipitation, evapotranspiration, soil moisture, streamflow, lakes and wetlands, ice and snow, and groundwater, as well as their implications for future water availability for humans and ecosystems. The chapter concludes with a synthesis discussion of three examples of complex regional-scale hydroclimate processes that influence water availability for populations in the United States, including (1) mountain and coastal precipitation, (2) aridification and drought, and (3) the influence of forest-cover change on terrestrial water-vapor recycling.

Professional Paper↗
USGS2021

Novel insights into the genetic population connectivity of transient whale sharks (Rhincodon typus) in Pacific Panama provide crucial data for conservation efforts

The whale shark ( Rhincodon typus ) is an endangered and highly migratory species, of which solitary individuals or aggregations are observed in oceans worldwide and for which conservation efforts are hindered by a lack of comprehensive data on genetic population connectivity. Tissue samples were collected from wandering whale sharks in Pacific Panama to determine genetic diversity, phylogeographic origin, and possible global and local connectivity patterns using a 700–800 bp fragment of the mitochondrial control region gene. Genetic diversity among samples was high, with five new haplotypes and nine polymorphic sites identified among the 15 sequences. Haplotype diversity ( H d = 0.83) and nucleotide diversity (π = 0.00516) were similar to those reported in other studies. Our sequences, in particular haplotypes PTY1 and PTY2 , were similar to those previously reported in the Arabian Gulf and the Western Indian Ocean populations (a novel occurrence in the latter case). Haplotypes PTY3 , PTY4 , and PTY5 were similar to populations in Mexico and the Gulf of California. In contrast, the only populations to which our Panamanian sequences were genetically dissimilar were those from the Atlantic Ocean. The absence of reference sequences in GenBank from southern sites in the Eastern Tropical Pacific, such as Galapagos (Ecuador), Gorgona and Malpelo Islands (Colombia), and Coco Island (Costa Rica), reduced our capacity to genetically define regional patterns. Genetic differentiation and connectivity were also assessed using an analysis of molecular variance (AMOVA), which showed a similar population structure (five groups) to the neighbor-joining tree. Other population features based on neutrality tests, such as Tajima’s D and Fu’s Fs statistics, showed positive values for Panama of 0.79 and 1.61, respectively. Positive values of these statistics indicate a lack of evidence for population expansion among the sampled individuals. Our results agree with previous reports suggesting that whale sharks can travel over long distances and that transboundary conservation measures may be effective for species protection.

Gulf of Chiriqu↗
USGS2012

National climate assessment technical report on the impacts of climate and land use and land cover change

This technical report responds to the recognition by the U.S. Global Change Research Program (USGCRP) and the National Climate Assessment (NCA) of the importance of understanding how land use and land cover (LULC) affects weather and climate variability and change and how that variability and change affects LULC. Current published, peer-reviewed, scientific literature and supporting data from both existing and original sources forms the basis for this report's assessment of the current state of knowledge regarding land change and climate interactions. The synthesis presented herein documents how current and future land change may alter environment processes and in turn, how those conditions may affect both land cover and land use by specifically investigating, * The primary contemporary trends in land use and land cover, * The land-use and land-cover sectors and regions which are most affected by weather and climate variability,* How land-use practices are adapting to climate change, * How land-use and land-cover patterns and conditions are affecting weather and climate, and * The key elements of an ongoing Land Resources assessment. These findings present information that can be used to better assess land change and climate interactions in order to better assess land management and adaptation strategies for future environmental change and to assist in the development of a framework for an ongoing national assessment.

Open-File Report↗
USGS2007

United States‐Mexican border watershed assessment: Modeling nonpoint source pollution in Ambos Nogales

Ecological considerations need to be interwoven with economic policy and planning along the United States‐Mexican border. Non‐point source pollution can have significant implications for the availability of potable water and the continued health of borderland ecosystems in arid lands. However, environmental assessments in this region present a host of unique issues and problems. A common obstacle to the solution of these problems is the integration of data with different resolutions, naming conventions, and quality to create a consistent database across the binational study area. This report presents a simple modeling approach to predict nonpoint source pollution that can be used for border watersheds. The modeling approach links a hillslopescale erosion‐prediction model and a spatially derived sediment‐delivery model within a geographic information system to estimate erosion, sediment yield, and sediment deposition across the Ambos Nogales watershed in Sonora, Mexico, and Arizona. This paper discusses the procedures used for creating a watershed database to apply the models and presents an example of the modeling approach applied to a conservation‐planning problem.

Arizona, Sonoma↗
USGS2010

Thermal Maturity Data Used by the U.S. Geological Survey for the U.S. Gulf Coast Region Oil and Gas Assessment

The U.S. Geological Survey is currently assessing the oil and natural gas resources of the U.S. Gulf of Mexico region using a total petroleum system approach. An essential part of this geologically based method is evaluating the effectiveness of potential source rocks in the petroleum system. The purpose of this report is to make available to the public RockEval and vitrinite reflectance data from more than 1,900 samples of Mesozoic and Tertiary rock core and coal samples in the Gulf of Mexico area in a format that facilitates inclusion into a geographic information system. These data provide parameters by which the thermal maturity, type, and richness of potential sources of oil and gas in this region can be evaluated.

Open-File Report↗