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The positions of shorelines and the areal extent of adjacent coastal wetland tracts in the Great Lakes region have exhibited substantial temporal variability during both prehistoric and historical times. Shoreline migration has resulted in environmental problems such as flooding and the coastal erosion of lakefront property, as well as the...

Coastal wetland ecosystems along the Great Lakes shorelines are extremely valuable natural resources. They provide numerous environmental and recreational benefits, and they serve as critical habitats for fish and wildlife populations. In general terms, wetlands can be defined as lands transitional between terrestrial and aquatic systems; they are characterized by...

The groundwater-flow system of the Virginia Coastal Plain consists of areally extensive and interconnected aquifers. Large, regionally coalescing cones of depression that are caused by large withdrawals of water are found in these aquifers. Local groundwater systems are affected by regional pumping, because of the interactions within the system of...

INTERACTIVE WORKSHOPS: ESSENTIAL ELEMENTS OF THE EARTHQUAKE HAZARDS RESEARCH AND REDUCTION PROGRAM IN THE WASATCH FRONT, UTAH: Interactive workshops provided the forum and stimulus necessary to foster collaboration among the participants in the multidisciplinary, 5-yr program of earthquake hazards reduction in the Wasatch Front, Utah. The workshop process validated well-documented...

In 1982, Glacier National Park (GNP) initiated long-term studies to document the fire history of all forested lands in the 410,000 ha. park. To date, studies have been conducted for GNP west of the Continental Divide (Barrett et al. 1991), roughly half of the total park area. These...

A vector-based geographical information system (GIS) is used to generate a variably-sized triangular element finite-element mesh from mappable features. Important digitally-mapped features are automatically linked to nodes in the finite-element model, ensuring an efficient, virtually error-free alternative to the tedious process of mesh design and data-input preparation by other methods....

Three modern sedimentary environments have been identified and mapped across the glaciated Boston Harbor estuary and adjacent inner shelf of Massachusetts Bay by means of an extensive set of sidescan sonar records and supplemental bathymetric, sedimentary, subbottom and bottom-current data. 1. (1) Environments of erosion and nondeposition appear on the...

This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower cast rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably...

Quantitative approaches to data analysis in the last decade have become important in basin modeling and mineral-resource estimation. The interrelation of geological, geophysical, geochemical, and geohydrological variables is important in adjusting a model to a real-world situation. Revealing the interdependences of variables can contribute in understanding the processes interacting in...

A geographic information system (GIS) was used to compile a series of databases containing details concerning metal contamination and pollution sources to study their impacts on the Galveston Bay (TX) ecosystem. Using these databases, a series of maps with various overlays was created with ARC/INFO software. These maps allowed patterns...

ALACARTE offers a convenient way to compile geologic maps in the computer as spatial databases that can be used to prepare both cartographic images and analytic derivatives. It is a menu-controlled shell, organized in geologic terms, that provides on-screen control of the program ARC/INFO, a commercial geographic information system (GIS). Input can...

ALACARTE offers a convenient way to compile geologic maps in the computer as spatial databases that can be used to prepare both cartographic images and analytic derivatives. It is a menu-controlled shell, organized in geologic terms, that provides on-screen control of the program ARC/INFO, a commercial geographic information system (GIS). Input can...

ALACARTE offers a convenient way to compile geologic maps in the computer as spatial databases that can be used to prepare both cartographic images and analytic derivatives. It is a menu-controlled shell, organized in geologic terms, that provides on-screen control of the program ARC/INFO, a commercial geographic information system (GIS). Input can...

The paleoclimatic informations preserved at some selected sites from high northern latitudes correlative with the last interglacial maximum of Isotopic Substage 5e have been compiled on a hemisphere scale. The mapped compilation reveals much warmer climate conditions on average than present in both terrestrial and marine environments, and indicates a...

Louisiana's coastal wetlands support a large percentage of the nation's seafood and fur industries, vast deposits of oil and natural gas, habitat for thousands of species of plants and animals, winter nesting grounds and migratory paths for numerous waterfowl, and many recreational resources enjoyed by residents and tourists. Louisiana's wetlands...

The US Geological Survey collects and disseminates, in written and digital formats, groundwater and surface-water information related to the tidal and nontidal wetlands of the United States. This information includes quantity, quality, and availability of groundwater and surface water; groundwater and surface-water interactions (recharge-discharge); groundwater flow; and the basic surface-water...

Online catalogs are computerized listings of materials in a particular library or group of libraries. General characteristics of online catalogs include ability for searching interactively and for locating descriptions of books, maps, and reports on regional or topical geology. Suggestions for searching, evaluating results, modifying searches, and limitations of searching...

Bowers Swell is a newly discovered bathymetric feature which is up to 90 m high, between 12 and 20 km wide, and which extends arcuately about 400 km along the northern and eastern sides of Bowers Ridge. The swell was first revealed on GLORIA sonographs and subsequently mapped on seismic...

In the process of developing a continuous hydrographic data layer for water resources applications in the Pacific Northwest, map-edge discontinuities in the U.S. Geological Survey 1:100 ,000-scale digital data that required application of computer-assisted edgematching procedures were identified. The spatial data sets required by the project must have line features...

The chemical quality of the ground water in the Floridan aquifer system is determined primarily by mineral-water interaction. However, some changes in water quality have been imposed by development, particularly near coastal pumping centers. A total of 601 chemical analyses, all from different wells, most completed in the upper part...

The changes in water levels in the High Plains aquifer from the nonirrigation season 1986-87 through the nonirrigation season 1987-88 and from the nonirrigation season 1979-80 through the nonirrigation season 1987-88 are presented in maps for the entire High Plains aquifer area. Water level changes are caused by interacting changes...

Intercepted intracell flow, especially if cell includes water table recharge and a stream ((sink), can result in significant model error if not accounted for. A procedure utilizing net flow per cell (Fn) that accounts for intercepted intracell flow can be used for both steady state and transient simulations. Germane to...

A dynamic source model is presented, in which a three-dimensional crack containing a viscous compressible fluid is excited into resonance by an impulsive pressure transient applied over a small area ΔS of the crack surface. The crack excitation depends critically on two dimensionless parameters called the crack stiffness, C = (b/μ)(L/d), and...

The shoreline of the tidal Potomac River attained its present form as a result of the Holocene episode of sea-level rise; the drowned margins of the system are modified by wave activity in the shore zone and by slope processes on banks steepened by basal-wave erosion. Shore erosion leaves residual...