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At least 271 records · Page 15Linked to original sources

USGS2020

Latency of waveform data delivery from the Southern California Seismic Network during the 2019 Ridgecrest earthquake sequence and its effect on ShakeAlert

The occurrence of the 4–6 July 2019 M w 6.4 and M w 7.1 Ridgecrest earthquake sequence provided the first full‐scale test of the network and telemetry readiness of the Southern California Seismic Network (SCSN), to support the ShakeAlert earthquake early warning (EEW) system in California. ShakeAlert is a U.S. Geological Survey (USGS)‐led collaboration to detect earthquakes and, when possible, to alert the public before the arrival of the strongest shaking. The SCSN performed well in its regional monitoring role for both the 4 July M w 6.4 and the 6 July M w 7.1 earthquakes. In the EEW role, it provided timely delivery of 5 s of P ‐wave data to ShakeAlert, which issued its first alert 6.9 s after origin time. Data delivery at peak data volumes for many stations exhibited some latency, and, as a consequence, some data arrived too late for analysis by one of the EEW algorithms. We find that the average link bandwidth for each station was sufficient, because all waveform data were delivered automatically to the archive, but link capacity for many stations was insufficient for peak demand. We describe the performance of the data telemetry for the sequence, including cellular, radio, hybrid, and backhaul systems. Cellular‐based telemetry systems maintained low latency throughout strong shaking and after, but some stations, even at great distances, experienced subsequent brief increases in latency. Performance of radio links depended mostly on the signal strength of the link, with short‐distance direct shots to high‐bandwidth backhaul systems showing no latency impact, whereas stations on some long distance or marginal quality links suffered latencies of tens or hundreds of seconds. Improvements are being implemented to move telemetry links onto USGS and partner high‐bandwidth microwave systems, and to reduce dependency on less robust long‐distance radio shots.

California↗

USGS2008

Hazard information management during the autumn 2004 reawakening of Mount St. Helens volcano, Washington

The 2004 reawakening of Mount St. Helens quickly caught the attention of government agencies as well as the international news media and the public. Immediate concerns focused on a repeat of the catastrophic landslide and blast event of May 18, 1980, which remains a vivid memory for many individuals. Within several days of the onset of accelerating seismicity, media inquiries increased exponentially. Personnel at the U.S. Geological Survey, the Pacific Northwest Seismic Network, and the Gifford Pinchot National Forest soon handled hundreds of press inquiries and held several press briefings per day. About one week into the event, a Joint Information Center was established to help maintain a consistent hazard message and to provide a centralized information source about volcanic activity, hazards, area closures, and media briefings. Scientists, public-affairs specialists, and personnel from emergency-management, health, public-safety, and land-management agencies answered phones, helped in press briefings and interviews, and managed media access to colleagues working on science and safety issues. For scientists, in addition to managing the cycle of daily fieldwork, challenges included (1) balancing accurate interpretations of data under crisis conditions with the need to share information quickly, (2) articulating uncertainties for a variety of volcanic scenarios, (3) minimizing scientific jargon, and (4) frequently updating and effectively distributing talking points. Success of hazard information management during a volcanic crisis depends largely on scientists’ clarity of communication and thorough preplanning among interagency partners. All parties must commit to after-action evaluation and improvement of communication plans, incorporating lessons learned during each event.

Washington↗

USGS2010

Old data, new problems

Old data are a gold standard in climate change research, and much more use should be made of these data sets to document changes in wetlands in recent decades. Key data sets for the study of climate or land use change effects on wetlands may include historical field studies. Old data sets such as those from Iowa State University in the 1980s have immense value for assessing long term vegetation change over time. These data sets include classic studies of biomass production, decomposition, vegetation composition, water level tolerances, and seed bank structure.

SWS Research Brief↗

USGS1964

Records of wells and springs, water levels, and chemical quality of ground water in the East Portland area, Oregon

Data are presented on more than 300 wells , including many new ones whose records will not be a part of a forthcoming interpretative report on the occurrence of ground water in this area . A brief description of the geomorphic features is given, and the characteristics of the rock units are summarized in a table. Principal aquifers are beds of loose sand and gravel in the early Pliocene Troutdale Formation, late Pleistocene fluviolacustrine deposits, and Recent alluvium. Locally, Columbia River Basalt (Miocene) and the Boring Lava (late Pliocene to Pleistocene) yield substantial amounts of wate.. In addition to well records there are 124 driller's logs and a table of chemical analyses of the ground water .

Oregon↗

USGS2002

Regional fluid flow as a factor in the thermal history of the Illinois basin: Constraints from fluid inclusions and the maturity of Pennsylvanian coals

Vitrinite reflectance measurements on Pennsylvanian coals in the Illinois basin indicate significantly higher thermal maturity than can be explained by present-day burial depths. An interval of additional sedimentary section, now removed by erosion, has been suggested to account for the discrepancy. Although burial could indeed account for the observed maturity levels of organic matter, fluid-inclusion temperatures provide a stringent additional constraint. In this article, we combine measurements of coal maturity with fluid-inclusion temperatures from three sites to constrain the basin's thermal and burial history: the Fluorspar district at the Illinois basin's southern margin, the Upper Mississippi Valley zinc district at the basin's northern margin, and a north-central location. Two-dimensional numerical modeling of a north-south cross section through the basin tests scenarios both with and without regional fluid flow. Vitrinite reflectance values can be matched assuming burial by 1.8-2.8 km of southward-thickening additional, post-Pennsylvanian sedimentary section. In the central and northern Illinois basin, however, these burial depths and temperatures are not sufficient to account for the fluid-inclusion data. To account for both parameters with burial alone does not appear feasible. In contrast, our best hypothesis assumes a wedge of post-Pennsylvanian sediment-thickening southward to about 1.2 km and a brief period of magmatism in the Fluorspar district. Significant advective heat redistribution by northward regional fluid flow accounts for fluid-inclusion temperatures and coal maturities throughout the basin. The modeling results demonstrate the potential contribution of advective heat transport to the thermal history of the Illinois basin.

Illinois, Indiana, Kentucky↗

USGS2008

Catalog of Mount St. Helens 2004-2007 dome samples with major- and trace-element chemistry

Sampling and analysis of eruptive products at Mount St. Helens is an integral part of volcano monitoring efforts conducted by the U.S. Geological Survey?s Cascades Volcano Observatory (CVO). The objective of our eruption sampling program is to enable petrological assessments of pre-eruptive magmatic conditions, critical for ascertaining mechanisms for eruption triggering and forecasting potential changes in eruption behavior. This report provides a catalog of near-vent lithic debris and new dome-lava collected during 34 intra-crater sampling forays throughout the October 2004 to October 2007 (2004-7) eruptive interval at Mount St. Helens. In addition, we present comprehensive bulk-rock geochemistry for a time-series of representative (2004-7) eruption products. This data, along with that in a companion report on Mount St. Helens 2004 to 2006 tephra by Rowe and others (2008), are presented in support of the contents of the U.S. Geological Survey Professional Paper 1750 (Sherrod and others, eds., 2008). Readers are referred to appropriate chapters in USGS Professional Paper 1750 for detailed narratives of eruptive activity during this time period and for interpretations of sample characteristics and geochemical data. The suite of rock samples related to the 2004-7 eruption of Mount St. Helens and presented in this catalog are archived at the David A. Johnson Cascades Volcano Observatory, Vancouver, Wash. The Mount St. Helens 2004-7 Dome Sample Catalogue with major- and trace-element geochemistry is tabulated in 3 worksheets of the accompanying Microsoft Excel file, of2008-1130.xls. Table 1 provides location and sampling information. Table 2 presents sample descriptions. In table 3, bulk-rock major and trace-element geochemistry is listed for 44 eruption-related samples with intra-laboratory replicate analyses of 19 dacite lava samples. A brief overview of the collection methods and lithology of dome samples is given below as an aid to deciphering the dome sample catalog. This is followed by an explanation of the categories of sample information (column headers) in Tables 1 and 2. A summary of the analytical methods used to obtain the geochemical data in this report introduces the presentation of major- and trace-element geochemistry of 2004-7 Mount St. Helens dome samples in table 3. Intra-laboratory results for the USGS AGV-2 standard are presented (tables 4 and 5), which demonstrate the compatibility of chemical data from different sources.

Open-File Report↗

USGS1999

Applications and issues of GIS as tool for civil engineering modeling

A tool that has proliferated within civil engineering in recent years is geographic information systems (GIS). The goal of a tool is to supplement ability and knowledge that already exists, not to serve as a replacement for that which is lacking. To secure the benefits and avoid misuse of a burgeoning tool, engineers must understand the limitations, alternatives, and context of the tool. The common benefits of using GIS as a supplement to engineering modeling are summarized. Several brief case studies of GIS modeling applications are taken from popular civil engineering literature to demonstrate the wide use and varied implementation of GIS across the discipline. Drawing from the case studies, limitations regarding traditional GIS data models find the implementation of civil engineering models within current GIS are identified and countered by discussing the direction of the next generation of GIS. The paper concludes by highlighting the potential for the misuse of GIS in the context of engineering modeling and suggests that this potential can be reduced through education and awareness. The goal of this paper is to promote awareness of the issues related to GIS-based modeling and to assist in the formulation of questions regarding the application of current GIS. The technology has experienced much publicity of late, with many engineers being perhaps too excited about the usefulness of current GIS. An undoubtedly beneficial side effect of this, however, is that engineers are becoming more aware of GIS and, hopefully, the associated subtleties. Civil engineers must stay informed of GIS issues and progress, but more importantly, civil engineers must inform the GIS community to direct the technology development optimally.

Journal of Computing in Civil Engineering↗

USGS2021

Three-dimensional geologic map of the Brady geothermal area, Nevada

The three-dimensional (3D) geologic map characterizes the subsurface in the Brady geothermal area in the northern Hot Springs Mountains of northwestern Nevada. We built the 3D map by integrating the results from detailed geologic mapping, seismic-reflection, potential-field-geophysical, and lithologic well-logging investigations completed in the study area. This effort was undertaken to investigate the geologic structure in the geothermal field and geologic controls on hydrothermal circulation. This characterization of the controls on hydrothermal circulation is applicable to the assessment, exploration, and development of analogous geothermal resources. The 3D map area is 4 kilometers (km) wide along the west-northwest-to-east-southeast axis and 6 km wide along the north-northeast-to-south-southwest axis and extends to 1.0 km below sea level, approximately 2.5 km below the land surface. We describe the geologic units and structures in the map area, discuss the methods used to integrate the geologic and geophysical information into the 3D geologic interpretation, and calculate several geologic factors that may aid in our understanding of hydrothermal circulation. Map sheet 1 provides horizontal and vertical section views and oblique perspective views from several angles of the 3D geologic map. Map sheet 2 provides views of derivative calculations based on the 3D geologic data, 3D density of faults, 3D density of fault intersections and terminations, slip tendency on 3D faults, and dilation tendency on 3D faults. We provide digital data for all elements of the map, such as individual 3D fault and stratigraphic surfaces, 3D fault density, 3D fault intersection density, 3D slip tendency on fault surfaces, and 3D dilation tendency on fault surfaces. A brief movie displaying the 3D map is available at https://doi.org/10.3133/sim3469 .

Nevada↗

USGS2010

Inter-comparison of hydro-climatic regimes across northern catchments: Synchronicity, resistance and resilience

The higher mid-latitudes of the Northern Hemisphere are particularly sensitive to climate change as small differences in temperature determine frozen ground status, precipitation phase, and the magnitude and timing of snow accumulation and melt. An international inter-catchment comparison program, North-Watch, seeks to improve our understanding of the sensitivity of northern catchments to climate change by examining their hydrological and biogeochemical responses. The catchments are located in Sweden (Krycklan), Scotland (Mharcaidh, Girnock and Strontian), the United States (Sleepers River, Hubbard Brook and HJ Andrews) and Canada (Catamaran, Dorset and Wolf Creek). This briefing presents the initial stage of the North-Watch program, which focuses on how these catchments collect, store and release water and identify 'types' of hydro-climatic catchment response. At most sites, a 10-year data of daily precipitation, discharge and temperature were compiled and evaporation and storage were calculated. Inter-annual and seasonal patterns of hydrological processes were assessed via normalized fluxes and standard flow metrics. At the annual-scale, relations between temperature, precipitation and discharge were compared, highlighting the role of seasonality, wetness and snow/frozen ground. The seasonal pattern and synchronicity of fluxes at the monthly scale provided insight into system memory and the role of storage. We identified types of catchments that rapidly translate precipitation into runoff and others that more readily store water for delayed release. Synchronicity and variance of rainfall-runoff patterns were characterized by the coefficient of variation (cv) of monthly fluxes and correlation coefficients. Principal component analysis (PCA) revealed clustering among like catchments in terms of functioning, largely controlled by two components that (i) reflect temperature and precipitation gradients and the correlation of monthly precipitation and discharge and (ii) the seasonality of precipitation and storage. By advancing the ecological concepts of resistance and resilience for catchment functioning, results provided a conceptual framework for understanding susceptibility to hydrological change across northern catchments. ?? 2010 John Wiley & Sons, Ltd.

Hydrological Processes↗

USGS1950

Preliminary report on selected sections of Lisburne Limestone, Brooks Range, Alaska

Location: - This report describes sections of the Lisburne limestone studied in the foothills and northern mountains of the Brooks Range, Alaska. The area covered extends along the front of the range from Sagavanirktok Lake (68°28' N. - 149°25' W.) west to the head of the Kukpowruk River (68°25' N. - 162°40' W.). The southernmost point in the area is at the head of Alapah Creek (68°11' N. - 150°40' W.) and the northernmost point is on Lisburne Ridge just west of the Etivluk River (68°36' N. - 156°40' W.). Field work was done by the authors at Sagavanirktok Lake, Kanayut Lake, Alapah Creek, the Anaktuvuk and Tiglukpuk Creek, and Chandler Lake. Brief visits were made to the Lisburne Ridge just north and west of the junction of the Nigu and Etivluk Rivers and to outcrops of Lisburne limestone along the Kiligwa River (68°30' N. - 158°35' W.). Data from other areas included in this report were collected by other field parties of the U. S. Geological Survey. A. L. Bowsher, Sr. .and J. T. Dutro, Jr. studied the Lisburne limestone at Kanayut Lake, Nanushuk Lake, and Itkillik Lake in 1949 1 / .W. W. Patton, Jr. and Irving L. Tailleur described the Lisburne limestone exposed in the northern Brooks Range along the Kiruktagiak River 2 / and the Okokmilage River 3 / in1949, and I. L. Tailleur and Bion H. Kent have supplied data on the Etivluk-Kiligwa Rivers area from their field work of 1950 4 /. R. M. Chapman, G. D. Eberlein, and C. D. Reynolds measured sections of Lisburne limestone at Kurupa Lake and on the east fork of the Etivluk River in 1950 5 /. E. G. Sable and M. D. Mangus measured the section on Iligluruk Creek near the head of the Kokolik River in 1950 6 /,, and Chapman end Sable measured the section at the head of the Kukpowrok River in 1949 7 /.

Alaska↗

USGS2015

USGS compilation of geographic information system (GIS) data representing coal mines and coal-bearing areas in China

Geographic information system (GIS) information may facilitate energy studies, which in turn provide input for energy policy decisions. The U.S. Geological Survey (USGS) has compiled geographic information system (GIS) data representing the known coal mine locations and coal-mining areas of China as of 2001. These data are now available for download, and may be used in a GIS for a variety of energy resource and environmental studies of China. Province-scale maps were also created to display the point locations of coal mines and the coal-mining areas. In addition, coal-field outlines from a previously published map by Dai and others (2012) were also digitized and are available for download as a separate GIS data file, and shown in a nation-scale map of China. Chemical data for 332 coal samples from a previous USGS study of China and Taiwan (Tewalt and others, 2010) are included in a downloadable GIS point shapefile, and shown on a nation-scale map of China. A brief report summarizes the methodology used for creation of the shapefiles and the chemical analyses run on the samples.

Open-File Report↗

USGS1999

Assessing biological effects from highway-runoff constituents

Increased emphasis on evaluation of nonpoint-source pollution has intensified the need for techniques that can be used to discern the toxicological effects of complex chemical mixtures. In response, the use of biological assessment techniques is receiving increased regulatory emphasis. When applied with documented habitat assessment and chemical analysis, these techniques can increase our understanding of the influence of environmental contaminants on the biological integrity and ecological function of aquatic communities. The contaminants of greatest potential concern in highway runoff are those that arise from highway construction, maintenance, and use. The major contaminants of interest are deicers; nutrients; metals; petroleum-related organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene, and xylene (BTEX), and methyl tert -butyl ether (MTBE); sediment washed off the road surface; and agricultural chemicals used in highway maintenance. Hundreds, if not thousands, of biological endpoints (measurable responses of living organisms) may be either directly or associatively affected by contaminant exposure. Measurable effects can occur throughout ecosystem processes across the wide range of biological complexity, ranging from responses at the biochemical level to the community level. The challenge to the environmental scientist is to develop an understanding of the relationship of effects at various levels of biological organization in order to determine whether a causal relationship exists between chemical exposure and substantial ecological impairment. This report provides a brief history of the evolution of biological assessment techniques, a description of the major classes of contaminants that are of particular interest in highway runoff, an overview of representative biological assessment techniques, and a discussion of data-quality considerations. Published reports with a focus on the effects of highway runoff on the local ecosystem were reviewed to provide information on (1) the suitability of the existing data for a quantitative national synthesis, (2) the methods available to study the effects of highway runoff on local ecosystems, and (3) the potential for adverse effects on the roadside environment and receiving waters. Although many biological studies have been done, the use of different methods and a general lack of sufficient documentation precludes a quantitative national synthesis on the basis of the existing data. The Federal Highway Administration, the U.S. Environmental Protection Agency, the U.S. Geological Survey, the Intergovernmental Task Force on Monitoring Water Quality, and the National Resources Conservation Service all have developed and documented methods for assessing the effects of contaminants on ecosystems in receiving waters. These published methods can be used to formulate a set of protocols to provide consistent information from highway-runoff studies. Review of the literature indicates (qualitatively) that highway runoff (even from highways with high traffic volume) may not usually be acutely toxic. Tissue analysis and community assessments, however, indicate effects from highway- runoff sediments near discharge points (even from sites near highways with relatively low traffic volumes). At many sites, elevated concentrations of highway-runoff constituents were measured in tissues of species associated with aquatic sediments. Community assessments also indicate decreases in the diversity and productivity of aquatic ecosystems at some sites receiving highway runoff. These results are not definitive, however, and depend on many site-specific criteria that were not sufficiently documented in most of the studies reviewed.

Open-File Report↗

USGS2005

Evaluation of Measurements Collected with Multi-Parameter Continuous Water-Quality Monitors in Selected Illinois Streams, 2001-03

Eight streams, representing a wide range of environmental and water-quality conditions across Illinois, were monitored from July 2001 to October 2003 for five water-quality parameters as part of a pilot study by the U.S. Geological Survey (USGS) in cooperation with the Illinois Environmental Protection Agency (IEPA). Continuous recording multi-parameter water-quality monitors were installed to collect data on water temperature, dissolved-oxygen concentrations, specific conductivity, pH, and turbidity. The monitors were near USGS streamflow-gaging stations where stage and streamflow are continuously recorded. During the study period, the data collected for these five parameters generally met the data-quality objectives established by the USGS and IEPA at all eight stations. A similar pilot study during this period for measurement of chlorophyll concentrations failed to achieve the data-quality objectives. Of all the sensors used, the temperature sensors provided the most accurate and reliable measurements (generally within ?5 percent of a calibrated thermometer reading). Signal adjustments and calibration of all other sensors are dependent upon an accurate and precise temperature measurement. The dissolved-oxygen sensors were the next most reliable during the study and were responsive to changing conditions and accurate at all eight stations. Specific conductivity was the third most accurate and reliable measurement collected from the multi-parameter monitors. Specific conductivity at the eight stations varied widely-from less than 40 microsiemens (?S) at Rayse Creek near Waltonville to greater than 3,500 ?S at Salt Creek at Western Springs. In individual streams, specific conductivity often changed quickly (greater than 25 percent in less than 3 hours) and the sensors generally provided good to excellent record of these variations at all stations. The widest range of specific-conductivity measurements was in Salt Creek at Western Springs in the Greater Chicago metropolitan area. Unlike temperature, dissolved oxygen, and specific conductivity that have been typically measured over a wide range of historical streamflow conditions in many streams, there are few historical turbidity data and the full range of turbidity values is not well known for many streams. Because proposed regional criteria for turbidity in regional streams are based on upper 25th percentiles of concentration in reference streams, accurate determination of the distribution of turbidity in monitored streams is important. Digital data from all five sensors were recorded within each of the eight sondes deployed in the streams and in automated data recorders in the nearby streamflow-gaging houses at each station. The data recorded on each sonde were retrieved to a field laptop computer at each station visit. The feasibility of transmitting these data in near-real time to a central processing point for dissemination on the World-Wide Web was tested successfully. Data collected at all eight stations indicate that a number of factors affect the dissolved-oxygen concentration in the streams and rivers monitored. These factors include: temperature, biological activity, nutrient runoff, and weather (storm runoff). During brief periods usually in late summer, dissolved-oxygen concentrations in half or more of the eight streams and rivers monitored were below the 5 milligrams per liter minimum established by the Illinois Pollution Control Board to protect aquatic life. Because the streams monitored represent a wide range in water-quality and environmental conditions, including diffuse (non-point) runoff and wastewater-effluent contributions, this result indicates that deleterious low dissolved-oxygen concentrations during late summer may be widespread in Illinois streams.

Scientific Investigations Report↗

USGS2023

Incorporating uncertainty in susceptibility criteria into probabilistic liquefaction hazard analysis

Most conventional approaches for assessing liquefaction triggering hazards generally rely on simplified procedures that involve identifying liquefaction susceptible layers and calculating a factor of safety against liquefaction (FSL) in each layer. Such procedures utilize deterministic semi-empirical models for standard penetration test (SPT), cone penetrometer test (CPT), or shear wave velocity (Vs)-based subsurface data. This general approach largely neglects considerable uncertainties in ground shaking, as well as aleatory variabilities and epistemic uncertainties inherent to liquefaction susceptibility and triggering prediction. A more robust methodology introduced by Kramer and Mayfield (2007) is known as probabilistic liquefaction hazard analysis (PLHA), which integrates the full ground motion hazard space with probabilistic forms of liquefaction triggering models (e.g., Boulanger and Idriss 2014), resulting in the computation of FSL profiles with consistent return periods. Multiple PLHA computational platforms have been developed over the years, with the computational framework from Makdisi (2021) serving as the basis for a new Liquefaction Hazard Tool under development at the U.S. Geologic Survey (USGS). Despite significant improvements in recent years to the availability of seismic hazard data and probabilistic triggering and effects models, the issue of incorporating uncertainty in characterizing liquefaction susceptibility remains a challenge. Most compositional susceptibility criteria (i.e., whether or not the soil exhibits sand-like behavior) currently in use are presented as deterministic bounds based on in-situ or laboratory test data; similarly, determination of soil saturation is often based on a single groundwater level from in-situ testing. As a result, the same types of binary decisions must be made in PLHA as in more conventional methods. With the expansion and availability of field and laboratory data pertaining to liquefaction through resources such as the Next Generation Liquefaction (NGL) project, there exists the potential for an improved set of susceptibility models for CPT, SPT, and Vs-based applications. Presented here is a brief discussion on how probabilistic susceptibility modeling can be accommodated in PLHA calculations, as well as how the use of multiple models can be leveraged within a logic tree to improve the representation of epistemic uncertainty in liquefaction hazard analysis.

Conference Paper↗

USGS2023

Paleomagnetically defined brief lifespans for two large shield volcanoes in the Cascades Arc

Mafic to intermediate shield volcanoes with multi-cubic-kilometer eruptive volumes are common in the Cascades Volcanic Arc, but little is known about their eruptive histories as either singular or sustained episodes, or the total time required for their construction. Paleomagnetic data were collected from the lava flows of Ash Creek Butte (17 sites) and Crater Mountain (14 sites) in northern California; both volcanoes are large shields with total volumes of ∼11 km 3 each. Tightly clustered paleomagnetic results at both volcanoes, when coupled with analysis of geomagnetic secular variation, suggest that each edifice was built in only a few centuries, possibly in as little time as 50–90 years, indicating sub-century to century scale eruptive durations for two sizeable regional shield volcanoes within the Cascades Arc. These rapidly built shield volcanoes are substantially larger than typically defined monogenetic volcanoes, yet both are wholly formed within a single ‘episode’ at the limits of temporal resolution. Paleomagnetic methods provide a high-resolution tool that can be applied to understanding the tempo of regional volcanism in arcs.

California, Oregon, Washington↗

USGS2015

An Arctic and Subarctic ostracode database: Biogeographic and paleoceanographic applications

A new Arctic Ostracode Database-2015 (AOD-2015) provides census data for 96 species of benthic marine Ostracoda from 1340 modern surface sediments from the Arctic Ocean and subarctic seas. Ostracoda is a meiofaunal, Crustacea group that secretes a bivalved calcareous (CaCO 3 ) shell commonly preserved in sediments. Arctic and subarctic ostracode species have ecological limits controlled by temperature, salinity, oxygen, sea ice, food, and other habitat-related factors. Unique species ecology, shell chemistry (Mg/Ca ratios, stable isotopes), and limited stratigraphic ranges make them a useful tool for paleoceanographic reconstructions and biostratigraphy. The database, described here, will facilitate the investigation of modern ostracode biogeography, regional community structure, and ecology. These data, when compared to downcore faunal data from sediment cores, will provide a better understanding of how the Arctic has been affected by climatic and oceanographic change during the Quaternary. Images of all species and biogeographic distribution maps for selected species are presented, with brief discussion of representative species’ biogeographic and ecological significance. Publication of AOD-2015 is open-sourced and will be available online at several public websites with latitude, longitude, water depth, and bottom water temperature for most samples. It includes material from Arctic abyssal plains and submarine ridges, continental slopes, and shelves of the Kara, Laptev, East Siberian, Chukchi, Beaufort Seas, and several subarctic regions.

Hydrobiologia↗

USGS1989

Geochemical evidence for invasion of Kilauea's plumbing system by Mauna Loa magma

From the beginning of the study of Hawaiian volcanism there has been controversy over possible relationships between the neighbouring active volcanoes Mauna Loa and Kilauea 1–5 . Seismic activity, thought to reflect upward migration of magma, reveals that the magmatic plumbing systems apparently converge at depth to form a broad funnel within the mantle 6 . Although on rare occasions they have erupted concurrently, the brief historical eruptive record appears to show that when Kilauea is most active, Mauna Loa is in repose and vice versa, suggesting that they may be competing for the same magma supply 5,7 . Petrological, geochemical and isotope data, however, require a diametrically opposite conclusion. Distinct differences in major-element, trace-element and isotope compositions of lavas are regarded as compelling evidence that the two volcanoes have separate magmatic plumbing systems, supplied by parental magmas from physically and geochemically distinct mantle sources 8–13 . Here we present preliminary geochemical data which show that in the past 2,000 years Kilauea has erupted a spectrum of lava compositions resembling historical Kilauea lavas at one end and Mauna Loa lavas at the other. We discuss the cause of this diversity, and speculate that magma from Mauna Loa may have invaded Kilauea's 'high-level' magmatic plumbing system.

Hawaii↗

USGS2014

Water resources of Jefferson Parish, Louisiana

This fact sheet presents a brief overview of groundwater and surface-water resources in Jefferson Parish, Louisiana. Information on the availability, use, and quality of water from groundwater and surface-water sources in the parish is discussed. Previously published reports and data stored in the U.S. Geological Survey’s National Water Information System ( http://waterdata.usgs.gov/nwis ) are the primary sources of this information.

Louisiana↗