Search USGS⌕ Search

SEARCH · Search USGS

Results for “Internal Report”

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

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

At least 739 records · Page 41Linked to original sources
USGS1970

Morphology, sedimentation, and seismic characteristics of an arctic beach, Nome, Alaska - with economic significances

Arctic beaches exhibit characteristics that do not occur on beaches in more temperate zones. In the summer of 1967 morphological, sedimentological, and seismic refraction studies were made on an arctic beach near Nome, Alaska, in order to better define these distinguishing characteristics. Several distinct microrelief structures are developed during ice break-up and the melting of ice and snow on the beaches including ice-pushed ridges, kaimoo ridge and deposits, sea-ice kettles, sea- ice sand and sea-ice gravel cones, micro-outwash deposits, and microdeltaic deposits. Sedimentological studies showed that sediment distribution along the beach is random with no increasing or decreasing median diameters, or sorting coefficients, or sand-gravel percentages, either along the strandline or along the beach profile. This random grain size distribution is attributed to the relatively low energy along the coast of the Seward Peninsula. Further, the beaches are insulated from the elements by ice for about 6 months out of the year and the beach sediments are disturbed annually by ice-push. Longshore drift appeared to vary from east to west during the summer of 1967 with a net transport to the east. The seismic refraction study on the Nome beach indicated that internal stratigraphy of the overburden could be interpreted and correlated with known onshore and offshore stratigraphic units. Bedrock was well defined in the seismograms and exhibited a gently undulating topography with several buried channels that may be sites of gold placer deposits.

Alaska↗
USGS1995

Ground-water and surface-water elevations in the Fairbanks International Airport area, Alaska, 1990-94

Ground-water and surface-water elevation data were collected at 52 sites from 1990 to 1994 by the U.S. Geological Survey in cooperation with the Alaska Department of Transportation and Public Facilities, Fairbanks International Airport. Water elevations were measured in 32 ground-water observation wells and at 20 surface-water sites to help characterize the geohydrology of the Fairbanks International Airport area. From 1990 to 1993, data were collected in the vicinity of the former fire-training area at the airport. From 1993 to 1994, the data-collection area was expanded to include the entire airport area.

Alaska↗
USGS2007

Ground-water recharge in the arid and semiarid southwestern United States: Climatic and geologic framework

Ground-water recharge in the arid and semiarid southwestern United States results from the complex interplay of climate, geology, and vegetation across widely ranging spatial and temporal scales. Present-day recharge tends to be narrowly focused in time and space. Widespread water-table declines accompanied agricultural development during the twentieth century, demonstrating that sustainable ground-water supplies are not guaranteed when part of the extracted resource represents paleorecharge. Climatic controls on ground-water recharge range from seasonal cycles of summer monsoonal and winter frontal storms to multimillennial cycles of glacial and interglacial periods. Precipitation patterns reflect global-scale interactions among the oceans, atmosphere, and continents. Large-scale climatic influences associated with El Niño and Pacific Decadal Oscillations strongly but irregularly control weather in the study area, so that year-to-year variations in precipitation and ground-water recharge are large and difficult to predict. Proxy data indicate geologically recent periods of multidecadal droughts unlike any in the modern instrumental record. Anthropogenically induced climate change likely will reduce ground-water recharge through diminished snowpack at higher elevations, and perhaps through increased drought. Future changes in El Niño and monsoonal patterns, both crucial to precipitation in the study area, are highly uncertain in current models. Land-use modifications influence ground-water recharge directly through vegetation, irrigation, and impermeable area, and indirectly through climate change. High ranges bounding the study area—the San Bernadino Mountains and Sierra Nevada to the west, and the Wasatch and southern Colorado Rocky Mountains to the east—provide external geologic controls on ground-water recharge. Internal geologic controls stem from tectonic processes that led to numerous, variably connected alluvial-filled basins, exposure of extensive Paleozoic aquifers in mountainous recharge areas, and distinct modes of recharge in the Colorado Plateau and Basin and Range subregions.

southwestern United States↗
USGS2000

Hydrology of the Helena area bedrock, west-central Montana, 1993-98

The Generalized Bedrock Geologic Map of the Helena Area, West-Central Montana (plate 1 in the report) provides an intermediate-scale overview of bedrock in the Helena area. The geologic map has been compiled at a scale of 1:100,000 from the most widely available sources of geologic map information (see index to geologic mapping on pl. 1). That information has been updated by M.W. Reynolds for this report with more recent geologic mapping and field revision of published maps. All well locations and all bedrock units penetrated during drilling have been confirmed on geologic maps at the largest scale available. Source geologic maps are all at scales larger than 1:100,000 scale. Care has been taken to ensure accurate representation of the original geology at the compilation scale. However, positional accuracy of some features might be somewhat diminished at the smaller scale of the base map when compared with the original data source. Also, line thicknesses for contacts and faults necessarily assume a greater width, relative to the real geologic feature, at the scale of the generalized map than on any original map. The map is not intended for large-scale, site-specific detailed planning. Bedrock units throughout the Helena area are generally covered by young surficial deposits such as alluvium, colluvium, glacial debris, or windblown sediment. Thickness of such deposits varies from veneers through which the underlying bedrock is clearly discernible to major thicknesses that conceal all underlying bedrock and structure. Boundaries of major accumulations of surficial deposits are attributed separately from bedrock contacts. These boundaries should not be considered precise at the map scale or at larger scales. Boundaries shown may be less accurate positionally than bedrock contacts and faults because (1) surficial deposits commonly thin to a knife edge; (2) different mappers will interpret the edge differently when drawing a boundary; or (3) the original geologic map maker was concerned principally with bedrock units and structure and thus overlooked, or did not originally map as consistently, some surficial deposits. Veneers of surficial sediment, when saturated, can be local sources of recharge to underlying bedrock. Use of the generalized map to define their distribution does not substitute for site specific mapping of such deposits. Specific knowledge is needed to determine the water-bearing properties of the geologic units at and surrounding a site because the units, including the igneous and metamorphic rocks, have internal differences in stratigraphy, composition, mineralogy and grain size or crystallinity. These differences, together with structural imprints such as faults, folds, and the spacing, orientation, degree of openness of fractures, and extent and type of mineral filling in fractures and faults, all affect the ability of rocks to store and transmit water.

Montana↗
USGS2000

Acoustic Doppler Current Profiler Data Processing System manual [ADCP]

This open-file report describes the data processing software currently in use by the U.S. Geological Survey (USGS), Woods Hole Coastal and Marine Science Center (WHCMSC), to process time series of acoustic Doppler current data obtained by Teledyne RD Instruments Workhorse model ADCPs. The Sediment Transport Instrumentation Group (STG) at the WHCMSC has a long-standing commitment to providing scientists high quality oceanographic data published in a timely manner. To meet this commitment, STG has created this software to aid personnel in processing and reviewing data as well as evaluating hardware for signs of instrument malfunction. The output data format for the data is network Common Data Form (netCDF), which meets USGS publication standards. Typically, ADCP data are recorded in beam coordinates. This conforms to the USGS philosophy to post-process rather than internally process data. By preserving the original data quality indicators as well as the initial data set, data can be evaluated and reprocessed for different types of analyses. Beam coordinate data are desirable for internal and surface wave experiments, for example. All the code in this software package is intended to run using the MATLAB program available from The Mathworks, Inc. As such, it is platform independent and can be adapted by the USGS and others for specialized experiments with non-standard requirements. The software is continuously being updated and revised as improvements are required. The most recent revision may be downloaded from: http://woodshole.er.usgs.gov/operations/stg/Pubs/ADCPtools/adcp_index.htm The USGS makes this software available at the user?s discretion and responsibility.

Open-File Report↗
USGS2024

Monitoring marine eruptions

Introduction Submarine volcanoes produce much of the same seismicity and eruptive activity as subaerial volcanoes and can pose hazards to society. Although they can be monitored with similar techniques and methods as described in other chapters of this volume, their submerged location brings unique challenges. This chapter addresses these challenges and provides recommendations for monitoring volcanoes fully or partly in marine environments to meet the capabilities described in other chapters of this volume. The United States and its territories host dozens of submarine volcanoes with most (around 60) in the Commonwealth of the Northern Mariana Islands. Approximately 20 of the Northern Mariana Islands submarine volcanoes are known to be hydrothermally active, and 10 have confirmed eruptions since the 1950s (for example, Baker and others, 2008; Tepp and others, 2019a). Nine of those volcanoes were considered by the National Volcanic Threat Assessment (Ewert and others, 2018) to have a combination of eruptive type and summit depth that poses a higher risk of hazardous eruptions, although only one was listed as a moderate (level 3) threat. Other notable submarine volcanoes of interest to the United States that have historically erupted are Axial Seamount off the Washington State coast, Kamaʻehuakanaloa in Hawaiʻi, and Vailuluʻu seamount in American Samoa. All of these, however, have a low risk of hazards because of their depth (greater than 600 meters below sea level) and eruptive type and so are not included in the National Volcanic Threat Assessment. In addition to submarine volcanoes, the submerged flanks of island volcanoes can also be a source of hazardous submarine eruptions—for example, the 1877 eruption of Mauna Loa, Hawai‘i, in Kealakekua Bay (Wanless and others, 2006). The most notable submarine eruption in recent times was the 2022 eruption of Hunga Tonga–Hunga Haʻapai in Tonga, which was one of the largest eruptions on Earth in the past 100 years. It created a massive volcanic plume, unprecedented shock waves, and far-reaching tsunami (Lynett and others, 2022). Other recent submarine eruptions in the Pacific Ocean Basin have produced subaerial plumes that reached aircraft heights (Carey and others, 2014) and large pumice rafts that can affect marine traffic and harbors (for example, Jutzeler and others, 2014; Kornei, 2019). These examples illustrate the potential hazards of major submarine eruptions. Yet, submarine volcanoes are largely unmonitored, and many eruptions occur that are unnoticed or only identified hours or days afterward. Within U.S. territory, submarine volcanoes in the Northern Mariana Islands have been known to produce eruptive activity that can affect society. Reports from fishermen and other marine vessels in the Northern Mariana Islands have noted underwater explosions, sea-surface discoloration, and bubbling water, all of which are known to be signs of submarine volcanic activity. South Sarigan seamount, located about 160 kilometers (km) north of Saipan, erupted in 2010 from greater than 150 meters below the sea surface, resulting in a gas and ash plume that reached more than 11.9 km into the atmosphere (for example, Searcy, 2013; Embley and others, 2014), high enough to affect international air traffic. Precursory and co-eruptive seismicity was detected on the regional Northern Mariana Islands seismic network (Searcy, 2013) and on global monitoring instruments (Green and others, 2013). Monitoring of submarine volcanoes is best accomplished with marine-based instrumentation, which is also useful for monitoring small island volcanoes that may not have the land area necessary for comprehensive subaerial monitoring. The primary marine-based instrumentation used for submarine volcanoes includes ocean-bottom pressure sensors to assess sea-floor deformation, ocean-bottom seismometers (OBSs) to detect seismicity, and both moored and ocean-bottom hydrophones to detect submarine explosions. Other sensors offer important monitoring data, such as turbidity, temperature, and chemistry of hydrothermal emissions. Marine-based instruments are typically deployed in campaign-style networks with no real-time telemetry owing to cost considerations and technical limitations. However, when necessary, marine instruments can be operated in real time using cables to transmit data to land-based facilities; other technologies for this purpose are in use or in development, such as acoustic transmission from the instrument to a moored buoy (Matsumoto and others, 2016) and a winch-based system with a satellite antenna that is part of the instrument mooring (Matsumoto and others, 2019). Emerging technologies for marine-based monitoring may be considered as part of a future monitoring plan. These technologies include ocean gliders and floats with on-board hydrophones that have been used to record earthquakes and submarine eruptions (for example, Matsumoto and others, 2013; Sukhovich and others, 2015) and fiber-optic cables that have been used as strainmeters to detect earthquakes (for example, Marra and others, 2018; Lindsey and others, 2019). Land-based instruments and satellites can also provide some capability for monitoring submarine volcanoes, but they provide more limited observations than marine-based instrumentation.

Scientific Investigations Report↗
USGS1966

Soviet books and publications on geological and chemical oceanography, hydrology, and other subjects acquired during the second international oceanographic congress, Moscow, June 1966: titles and some translated contents and notes

The listed publications represent a selection, by no means complete, of recent Soviet work in geological and chemical oceanography. Some works on hydrogeology and hydrochemistry of the continents, as well as a few publications on other subjects, such as geology, geophysics, and biology, also are included.

Report↗
USGS2013

Challenge theme 7: Information support for management of border security and environmental protection: Chapter 9 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

Historically, international borders were located far from the major political and economic capitals of their countries and rarely received adequate planning or infrastructure development. Today, as a result of global economics and increased movement of goods between nations, border regions play a much greater role in commerce, tourism, and transportation. For example, Mexico is the second largest destination for United States exports (Woodrow Wilson Center Mexico Institute, 2009). The rapid population and economic growth along the United States–Mexican border, undocumented human border crossings, and the unique natural diversity of resources in the Borderlands present challenges for border security and environmental protection. Assessing risks and implementing sustainable growth policies to protect the environment and quality of life greatly increase in complexity when the issues cross an international border, where social services, environmental regulations, lifestyles, and cultural beliefs are unique for each country. Shared airsheds, water and biological resources, national security issues, and disaster management needs require an integrated binational approach to assess risks and develop binational management strategies.

United States-Mexico Borderlands↗
USGS2007

Divisions of geologic time—Major chronostratigraphic and geochronologic units

Effective communication in the geosciences requires consistent uses of stratigraphic nomenclature, especially divisions of geologic time. A geologic time scale is composed of standard stratigraphic divisions based on rock sequences and calibrated in years. Over the years, the development of new dating methods and refinement of previous ones have stimulated revisions to geologic time scales. Since the mid-1990s, geologists from the U.S. Geological Survey (USGS), State geological surveys, academia, and other organizations have sought a consistent time scale to be used in communicating ages of geologic units in the United States. Many international debates have occurred over names and boundaries of units, and various time scales have been used by the geoscience community. For consistency purposes, the USGS Geologic Names Committee and the Association of American State Geologists developed Divisions of Geologic Time .

Fact Sheet↗
USGS2012

The state of amphibians in the United States

More than 25 years ago, scientists began to identify unexplained declines in amphibian populations around the world. Much has been learned since then, but amphibian declines have not abated and the interactions among the various threats to amphibians are not clear. Amphibian decline is a problem of local, national, and international scope that can affect ecosystem function, biodiversity, and commerce. This fact sheet provides a snapshot of the state of the amphibians and introduces examples to illustrate the range of issues in the United States.

Fact Sheet↗
USGS2025

U.S. Geological Survey streamgage network in the Upper Colorado River Basin—Recording the hydrologic history of the Western United States

Introduction Water supply in the Western United States is an essential resource, and the collection of accurate and timely water information is fundamental to effectively managing water resources in the region. Efforts to document the hydrology in the Colorado River Basin are vital to life in the Western United States. These efforts began as far back as the initial John Wesley Powell exploration of the Colorado River and its tributaries in the summer of 1869. Shortly after, the U.S. Geological Survey (USGS) was created in 1879, and the first USGS systematic measurement of streamflow began at the first streamgage, 08279500 Rio Grande at Embudo, New Mexico, in 1889. During its 146-year existence, the USGS has served the citizens of the United States in many roles, notably through long-standing stewardship in water science. For example, the USGS has collected hydrologic information at strategic locations within the Western United States to support water resource management, flood forecasting and response, interbasin water transfers, hydropower generation, municipal and agricultural water supplies, food security, recreation, habitat preservation, international treaty obligations and river compact compliance, and the operation of major water-storage projects, including Lake Powell and Lake Mead bordering Utah and Arizona, and Nevada and Arizona, respectively.

Arizona, Colorado, New Mexico, Utah, Wyoming↗
USGS2001

Hydrogeology, model description, and flow analysis of the Mississippi River alluvial aquifer in northwestern Mississippi

The Mississippi River alluvial aquifer underlies a 7,000-square-mile area of the Mississippi River alluvial plain in northwestern Mississippi, an area locally known as the Delta. The alluvial aquifer is the most heavily pumped aquifer in Mississippi, and wells yielding more than 2,000 gallons per minute are common. About 98 percent of the pumpage from the alluvial aquifer is for agriculture. The sand and gravel that form the alluvial aquifer averages about 110 feet in thickness. The aquifer is confined over most of the Delta, and the upper confining unit averages about 25 feet in thickness. The average depth to water in the alluvial aquifer during fall 1999 was about 25 feet. The alluvial aquifer receives lateral recharge at the western boundary from the Mississippi River and at the eastern boundary from aquifers that directly underlie the Bluff Hills. The alluvial aquifer receives water vertically from precipitation, internal streams and lakes, and locally from the Cockfield and Sparta aquifers where they directly underlie the alluvial aquifer. The alluvial aquifer also discharges water to the underlying aquifers, and during extended periods with no surface runoff, to the Mississippi River and to the internal streams and lakes. The magnitude of recharge from the Mississippi River, precipitation, and internal lakes and streams can vary greatly depending upon hydrologic and climatic conditions. The U.S. Geological Survey modular threedimensional finite-difference ground-water flow model, MODFLOW, was used to simulate the Mississippi River alluvial aquifer flow system in northwestern Mississippi. The model uses one layer with a rectangular-grid and 1-mile square cells to represent the alluvial aquifer. The model was calibrated and verified by using spring and fall water-level measurements from January 1988 through December 1996. The values of selected model calibration-derived parameters for the alluvial aquifer are hydraulic conductivity, 425 feet per day; specific yield, 0.32; and storage coefficient, 0.016. The model showed that the aquifer lost water from storage at an average rate of 404 cubic feet per second during the 9-year simulation period. During this period, the average pumpage rate was 1,270 million gallons per day (1,980 cubic feet per second). Simulated areal recharge from precipitation averaged 2.6 inches per year (1,360 cubic feet per second). Vertical recharge from the internal streams and lakes and lateral recharge from aquifers underlying the Bluff Hills averaged 113 and 108 cubic feet per second, respectively. Model results indicated that net recharge from the Mississippi River and from aquifers directly underlying the alluvial aquifer was small.

Mississippi↗
USGS2022

Science mission requirements for a globally ranging, riserless drilling vessel for U.S. Scientific Ocean Drilling

Through the collection and analysis of shallow and deep subseafloor sediments, rocks, fluids, and life, scientific ocean drilling has enriched our understanding of the complex Earth system. Among other achievements, scientific ocean drilling has documented the history of Earth’s climate, the waxing and waning of polar ice sheets, the past changes in ocean and atmospheric circulation, the existence and function of microbial life in the subseafloor, the compositional variations in Earth’s crust and underlying mantle, and the physical and chemical processes acting at subduction zones, including those associated with tsunamigenic earthquakes. Over the decades, more than 12,000 articles that depend on analyses of scientific ocean drilling samples and geophysical data have been published, many detailing breakthrough contributions to global knowledge about the Earth system. Approximately 45% of these publications were led by U.S.-affiliated authors (International Ocean Discovery Program Publication Services, 2021). Since the mid-1980s, the workhorse of this multidisciplinary, international research effort has been the riserless D/V JOIDES Resolution, operated by Texas A&M University with funding from the U.S. National Science Foundation (NSF). D/V JOIDES Resolution has conducted the vast majority of scientific ocean drilling expeditions and collected most of the scientific cores over that period, including 82% of the expeditions and 93% of the cores in the last decade alone, despite being one of three platforms that is operated within the International Ocean Discovery Program. However, D/V JOIDES Resolution is approaching the end of its useful life. With a strong commitment to continue scientific ocean drilling beyond the end of the current phase, the community developed a document outlining the research frontiers that should be pursued. Exploring Earth by Scientific Ocean Drilling: 2050 Science Framework (Koppers and Coggon, 2020) describes seven scientific strategic objectives that focus on understanding interconnections within the Earth system and five flagship initiatives that integrate these objectives into long-term research efforts that address issues facing society. Additional elements in the 2050 Science Framework, including STEM education, workforce development, technology development, and innovative applications of data analytics, will advance the goals of scientific ocean drilling. Addressing the 2050 Science Framework also requires building partnerships with allied U.S. and international science programs and strengthening existing ones. To implement a significant portion of the 2050 Science Framework, the U.S. scientific community seeks to lease or acquire a newly built, globally ranging, state-of-the art, riserless drilling vessel. The many and varied technical and human resources requirements for successful accomplishment of scientific and educational goals summarized in this document and described in detail in the 2050 Science Framework require broad community input and careful consideration. Following receipt of NSF’s formal Request for Assistance to the United States Science Support Program (USSSP), the U.S. scientific ocean drilling community conducted a one-year exercise to identify its national scientific needs and priorities in order to determine the Science Mission Requirements (SMRs) presented here. This community effort included: (1) a U.S. community-wide survey to identify the specific operational and technical capabilities critical to addressing science in the 2050 Science Framework; (2) a series of online workshops focusing on critical capabilities identified by the survey; and (3) a large in-person workshop to synthesize the results of the survey and the virtual workshops (Appendix 1). The approach was designed to reach as many participants as possible. Overall, 278 survey responses were received from U.S. community members, representing 104 unique institutions from 39 states and the District of Columbia, and 137 unique individuals participated in the workshops (Appendix 2). The results of this effort comprise two classes of SMRs: Foundational Science Mission Requirements and Primary Science Mission Requirements. Foundational SMRs define minimum criteria for a new riserless drilling vessel that can address significant portions of the 2050 Science Framework. Primary SMRs build upon the Foundational SMRs and will create more robust science opportunities and data collection capabilities, will increase progress in addressing the 2050 Science Framework objectives, and will provide more real-time ship-to-shore interaction to improve science productivity, engagement, and outreach. Modern safety and environmental standards, including meeting standards to access protected waters such as exclusive economic zones, extended continental shelves, or high latitudes, while being cognizant of the vessel’s environmental footprint. Safe and efficient operations in global locations and in water depths from 70 m to 6000+ m, with total drill string length of at least 7000 m. High-quality core and data collection from a range of key subseafloor environments. Advanced heave compensation, dynamic positioning, and drill pipe stability. Modern mud and cement/casing systems. Critical onboard measurements for safety, operational decision-making, documentation of ephemeral properties, mission-specific science, and long-term science goals that extend beyond a single expedition. Designated and appropriate space for sample and data preservation. Highly skilled onboard personnel, including technical staff for curation and core handling; support for safety, time-sensitive, and critical shipboard measurements; computer support; equipment and instrument repair; application support; and data assurance. Primary Science Mission Requirements include: Flexible shipboard space for laboratories and on deck to ensure safe, successful implementation of diverse science objectives and operations. Minimizing contamination of recovered samples. Over-the-side capabilities for science-supporting technology (e.g., remotely operated vehicles, water- column sampling, sediment-water interface sampling). Downhole logging and measurements. Expanded borehole observatory capabilities. Reliable and consistent ship-to-shore communications. NSF’s investment in a new globally ranging, riserless drilling vessel will have a powerful economic multiplier effect, including the infusion of additional science support funds in the United States for training and research, the development of new technologies and tools, and the associated scientific and technical workforce development. The skills and knowledge gained through scientific ocean drilling are translatable to careers in fields such as sustainable energy development (e.g., geothermal and offshore wind), carbon sequestration, data management and cyberinfrastructure, biotechnology, communications, science education, policy, hazard mitigation, and environmental management. The United States is a leader in a well-established and internationally collaborative scientific ocean drilling community. A modern, globally ranging, riserless drilling vessel will allow the United States to expand its leadership position, address broad scientific questions that current capabilities preclude, and cultivate equitable international, multidisciplinary collaborations that will ensure scientific ocean drilling’s future success.

Report↗
USGS1989

IRIS/USGS plans for upgrading the Global Seismograph Network

This report has been prepared to provide information to organizations that may be asked to participate in a program to upgrade the global seismographic network. In most cases, the organizations that will be offered new instrumentation by the U.S. Geological Survey currently operate stations in the World-Wide Standardized Seismograph Network (WWSSN) or the Global Digital Seismograph Network (GDSN). The deployment of the WWSSN in the 1960's and the subsequent equipping of some WWSSN stations with digital equipment and borehole seismometers during the 1970's has been a remarkably successful program that generated the high- quality data needed to fuel an unprecedented period of progress in earthquake and tectonic research. The success of the WWSSN can be attributed to the importance of the data, to the strong commitment by participating organizations to international scientific cooperation, to the dedication and skill of the station operators, and to the resourcefulness of the staff supporting the network. Benefits have been widespread. The community of scientists world-wide has benefited from unrestricted access to a standardized base of calibrated data, and the participating stations have benefited from the donation of modern observatory instruments that have been useful for local earthquake studies and for the training of scientists and engineers. Now, an exciting opportunity has arisen to deploy a new generation of seismograph systems to replace the outdated equipment at many of the WWSSN and GDSN stations. The U.S. Geological Survey (USGS) is cooperating with the Incorporated Research Institutions for Seismology (IRIS) in a program to upgrade the global seismograph network. The equipment development phase is nearly complete with a prototype of the new broadband seismograph system currently undergoing final testing at the USGS Albuquerque Seismological Laboratory. Deployment of the new equipment is expected to begin in early 1990. As this report will demonstrate, the IRIS broadband seismograph system combines the very latest data acquisition and computer technology to produce seismic data with unprecedented bandwidth and dynamic range. Moreover, the system has been designed so that the high-quality digital data are accessible for local display and analysis. The functional design of the new system, which uses off-the-shelf modules and a standard computer bus, will make it much easier than it has been in the past to modify and upgrade the data acquisition system as improvements in technology become available. With adequate support for the program, the new IRIS seismograph system need never become obsolete. We want you to be aware of our plans and the possibility that you may be asked to participate in this ,program. The schedule for upgrading WWSSN and GDSN stations depends on the level of funding earmarked for the program by our National Science Foundation. We hope to deploy at least ten new GSN data systems each year. If you have any questions concerning this program, please contact the Albuquerque Seismological Laboratory, U.S. Geological Survey, Albuquerque, New Mexico 87115-5000. This report was revised in February 1992 in order to update information concerning the current program and instrumentation. The amp in Figure 1 was revised in June 1993, April 1994, December 1994, and September 1996 to reflect updated siting information. In September 1996 a composite photo of standard and optional components of the IRIS-2 GSN system hardware was added as a separate page between Figures 9 and 10.

Open-File Report↗
USGS2004

Pesticide concentrations in water and in suspended and bottom sediments in the New and Alamo rivers, Salton Sea Watershed, California, April 2003

This report contains pesticide concentration data for water, and suspended and bed sediment samples collected in April 2003 from twelve sites along the New and Alamo Rivers in the Salton Sea watershed, in southeastern California. The study was done in collaboration with the California State Regional Water Quality Control Board, Colorado River Region, to assess inputs of current-use pesticides associated with water and sediment into the New and Alamo Rivers. Five sites along the New River and seven sites along the Alamo River, downstream of major agricultural drains, were selected and covered the lengths of the rivers from the international boundary to approximately 1.5 km from the river mouths. Sampling from bridges occurred at seven of the twelve sites. At these sites, streamflow measurements were taken. These same sites were also characterized for cross-stream homogeneity by measuring dissolved oxygen, pH, specific conductance, temperature, and suspended solids concentration at several vertical (depths) and horizontal (cross-stream) points across the river. Large volume water samples (200?300 L) were collected for isolation of suspended sediments by flow-through centrifugation. Water from the outflow of the flow-through centrifuge was sampled for the determination of aqueous pesticide concentrations. In addition, bottom sediments were sampled at each site. Current-use pesticides and legacy organochlorine compounds (p,p'-DDT, p,p'-DDE and p,p'-DDD) were extracted from sediments and measured via gas chromatography/mass spectrometry (GC/MS). Organic carbon and percentage of fines were also determined for suspended and bottom sediments. Cross-stream transects of dissolved constituents and suspended sediments showed that the rivers were fairly homogeneous at the sites sampled. Streamflow was higher at the outlet sites, with the Alamo River having higher flow (1,240 cfs) than the New River (798 cfs). Twelve current-use pesticides, one legacy organochlorine compound (p,p'-DDE), and the additive piperonyl butoxide were detected in water samples. Trifluralin was found in the highest concentration of all detected compounds (68.5?599 ng/L) at all sites in both rivers, except for the international boundary sites. Atrazine was also detected in high concentration (51.0?285 ng/L) at several sites. The outlet sites had among the highest numbers of pesticides detected and the international boundary sites had the lowest numbers of pesticides detected for both rivers. The numbers of pesticides detected were greater for the Alamo River than for the New River. Six current-use pesticides and two legacy organochlorines (p,p'-DDE and p,p'-DDD) were found associated with suspended and bed sediments. The DDT metabolite p,p'-DDE was detected in all suspended and bed sediments from the Alamo River, but only at two sites in the New River. Dacthal, chlorpyrifos, pendimethalin, and trifluralin were the most commonly detected current-use pesticides. Trifluralin was the compound found in the highest concentrations in suspended (14.5?120 ng/g) and bed (1.9?9.0 ng/g) sediments. The sites along the Alamo River had more frequent detections of pesticides in suspended and bed sediments when compared with the New River sites. The greatest number of pesticides that were detected in suspended sediments (seven) were in the samples from the Sinclair Road and Harris Road sites. For bottom sediments, the Alamo River outlet site had the greatest number of pesticide detections (eight).

Data Series↗
USGS1974

Geology of quadrangles H-12, H-13, and parts of I-12 and I-13, (zone III) in northeastern Santander Department, Colombia

A program of geologic mapping and mineral investigation in Colombia was undertaken cooperatively by the Colombian Instituto Nacional de Investigaciones Geologico-Mineras (formerly known as the Inventario Minero Nacional), and the U. S. Geological Survey; by the Government of Colombia and the Agency for International Development, U. S. Department of State. The purpose was to study, and evaluate mineral resources (excluding of petroleum, coal, emeralds, and alluvial gold) of four selected areas, designated Zones I to IV, that total about 70,000 km2. The work in Zone III, in the Cordillera Oriental, was done from 1965 to 1968. The northeast trend of the Cordillera Oriental of Colombia swings abruptly to north-northwest in the area of this report, and divides around the southern end of the Maracaibo Basin. This section of the Cordillera Oriental is referred to as the Santander Massif. Radiometric age determinations indicate that the oldest rocks of the Santander massif are Precambrian and include high-grade gneiss, schist, and migmatite of the Bucaramanga Formation. These rocks were probably part of the Precambrian Guayana Shield. Low- to medium-grade metamorphic rocks of late Precambrian to Ordovician age .include phyllite, schist, metasiltstone, metasandstone, and marble of the Silgara Formation, a geosynclinal series of considerable extent in the Cordillera Oriental and possibly the Cordillera de Merida of Venezuela. Orthogneiss ranging from granite to tonalite is widely distributed in the high- and medium-grade metamorphic rocks of the central core of the massif and probably represents rocks of two ages, Precambrian and Ordovician to Early Devonian. Younger orthogneiss and the Silgara are overlain by Middle Devonian beds of the Floresta Formation which show a generally low but varying degree of metamorphism. Phyllite and argillite are common, and infrequent marble and other calcareous beds are fossiliferous. Except for recrystallization in limestones of !the Permian-Carboniferous Diamante Formation, sedimentary rocks younger than Devonian are unmetamorphosed. The effects of Precambrian regional dynamothermal metamorphism and plutonism on Precambrian geosynclinal deposits reached the upper amphibolite facies in the Bucaramanga Gneiss. The geosynclinal Silgara Formation was subjected to similar conditions in Late Ordovician and Early Silurian time but reached only the greenschist or lower amphibolite facies. Orthogneisses generally show a concordance of foliation and lineation with the neighboring Silgara Formation and the Bucaramanga Gneiss as well as similarities in grade of metamorphism. Regional dynamothermal metamorphism in Late Permian and Triassic time reached, low grade in the Floresta Formation and caused recrystallization of limestone of the Diamante Formation. The Bucaramanga and Silgara metamorphic rocks show evidence of metrogressive metamorphism accompanied by high activity or potassium and water, but whether this occurred at the time the Floresta was metamorphosed or later is not clear. Batholiths, plutons, and stocks of igneous rocks in the Santander massif range from diorite to granite. Radioactive age data indicate that most belong to a single plutonic interval. These are referred to as the Santander Plutoniq Group and are Jurassic and Jurassic-Triassic- Two suites of this group are pink granite and quartz monzonite, and gray quartz monzonite and granodiorite. Contact relations indicate that the pink and more granitic rocks are younger than the gray and more mafic rocks, but radioactive age data are in conflict with this. Undated plutonic rocks that are not clearly related to the group are assigned to relatively older or younger age positions. West of the Bucanamanga fault rhyolite makes up a small body at one locality and forms an intrusive sheet with granophyre and intrusive breccias in Triassic sedimentary rocks at another locality. Its age is unknown, but it probably is younger than the

Open-File Report↗
USGS2015

Anatomy of an eradication effort: Removing Hawaii's illegally introduced axis deer

In February 2011, a rancher in the rural southern part of Hawaii Island reported a large mammal on her land. Her call mobilized several agencies led by the Big Island Invasive Species Committee (BIISC), a partnership to prevent, detect, and control the establishment and spread of invasive species, to sit up and take notice. Agency biologists installed camera traps to identify the animal, and a few months later verified the diagnostic field marks of a chervid with spots. The animal in questions was a chital , or axis deer ( Axis axis )--a species native to tropical and subtropical India. Although the deer are abundant on the islands of Molokai, Lānai, and Maui, officials knew they weren't capable of swimming across the notoriously treacherous ʻAlenuihāhā channel, and subsequently suspected human intervention. Soon after the rancher's report, the U.S. Fish and Wildlife Service launched an investigation, which revealed that in December 2009, a helicopter pilot and rancher from Maui had covertly transported four deer in exchange for about a dozen European mouflon sheep ( Ovis gmelini musimon ) (Tummons 2011a, b)--a species also valued for trophies and meat. Because neither species was established in the wild on either of the islands, in June 2012, state lawmakers responded by specifically banning "the international possession or interisland transportation or release of wild or feral deer" (Honolulu Star-Advertiser 2012). The two individuals were prosecuted under the Lacey Act for transporting wildlife between islands with the intent to guide hunting for out-of-state residents (Stephens Media 2012), while the individual who provided the mouflon was sentenced to community service. Further, the helicopter pilot agreed to provide 500 hours of flight time to locate and eradicate the Hawaii Island deer population in restitution.

Hawai'i↗
USGS2012

Surface-water radon-222 distribution along the west-central Florida shelf

In February 2009 and August 2009, the spatial distribution of radon-222 in surface water was mapped along the west-central Florida shelf as collaboration between the Response of Florida Shelf Ecosystems to Climate Change project and a U.S. Geological Survey Mendenhall Research Fellowship project. This report summarizes the surface distribution of radon-222 from two cruises and evaluates potential physical controls on radon-222 fluxes. Radon-222 is an inert gas produced overwhelmingly in sediment and has a short half-life of 3.8 days; activities in surface water ranged between 30 and 170 becquerels per cubic meter. Overall, radon-222 activities were enriched in nearshore surface waters relative to offshore waters. Dilution in offshore waters is expected to be the cause of the low offshore activities. While thermal stratification of the water column during the August survey may explain higher radon-222 activities relative to the February survey, radon-222 activity and integrated surface-water inventories decreased exponentially from the shoreline during both cruises. By estimating radon-222 evasion by wind from nearby buoy data and accounting for internal production from dissolved radium-226, its radiogenic long-lived parent, a simple one-dimensional model was implemented to determine the role that offshore mixing, benthic influx, and decay have on the distribution of excess radon-222 inventories along the west Florida shelf. For multiple statistically based boundary condition scenarios (first quartile, median, third quartile, and maximum radon-222 inshore of 5 kilometers), the cross-shelf mixing rates and average nearshore submarine groundwater discharge (SGD) rates varied from 100.38 to 10-3.4 square kilometers per day and 0.00 to 1.70 centimeters per day, respectively. This dataset and modeling provide the first attempt to assess cross-shelf mixing and SGD on such a large spatial scale. Such estimates help scale up SGD rates that are often made at 1- to 10-meter resolution to a coarser but more regionally applicable scale of 1- to 10-kilometer resolution. More stringent analyses and model evaluation are required, but results and analyses presented in this report provide the foundation for conducting a more rigorous statistical assessment.

Florida↗