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The U.S. Geological Survey (USGS) is updating and revising its 1996 national seismic-hazard maps for release in 2001. Part of this process is the convening of four regional workshops with earth scientists and other users of the maps. The second of these workshops was sponsored by the USGS and the...

No abstract available....

Gravity and aeromagnetic data provide insights into the subsurface lithology and structure of the Virgin River Depression (VRD) of Nevada, Utah, and Arizona. The gravity data indicate that the Quaternary and Tertiary sedimentary deposits hide a complex pre-Cenozoic surface. A north-northwest-trending basement ridge separates the Mesquite and Mormon basins, as...

Statistical summaries of high-streamflow data through water year 1997 for selected active U.S. Geological Survey gaging stations for the Red River of the North Basin upstream of and including Emerson, Manitoba, but excluding the Devils Lake Basin, are presented in this report. The summaries for each streamflow-gaging station include (1)...

No abstract available....

Mercury that was used historically for gold recovery in mining areas of the Sierra Nevada continues to enter local and downstream water bodies, including the Sacramento Delta and the San Francisco Bay of northern California. Methylmercury is of particular concern because it is the most prevalent form of mercury in...

Sedimentation in Crowders Creek cove in Lake Wylie, located in York County, South Carolina, has restricted boat navigation and made a boat ramp unusable. To provide baseline information, the U.S. Geological Survey, in cooperation with the York County Council, collected bathymetric and bed-sediment data in the cove, and streamflow and...

This report presents lithologic and ground-water-quality data collected during April and May 2000 in the remote areas of the tidal wetland of West Branch Canal Creek, Aberdeen Proving Ground, Maryland. Contamination of the Canal Creek aquifer with volatile organic compounds has been documented in previous investigations of the area. This...

This report presents water-quality data for ground-water and surface-water samples and water-level data collected by the U.S. Geological Survey from October 1998 through September 1999 at West Branch Canal Creek, Aberdeen Proving Ground, Maryland. The report also provides a description of the sampling and analytical methods that were used to...

Ground water in Triassic-age sedimentary fractured-rock aquifers in the area of Gettysburg, Pa., is used as drinking water and for industrial and commercial supply. In 1983, ground water at the Gettysburg Elevator Plant was found by the Pennsylvania Department of Environmental Resources to be contaminated with trichloroethene, 1,1,1-trichloroethane, and other...

In 1996-1998 the U.S. Geological Survey (USGS) conducted a geochemical study of the Bureau of Land Management’s (BLM) 5.5 million-acre Northern and Eastern Colorado Desert Resource Area (usually referred to as the NECD in this report), Imperial, Riverside, and San Bernardino Counties, southeastern California (figure 1). This study was done...

Flow-velocity and depth data were collected from July 1996 through December 1998 during peak discharge events at 21 bridge crossings that are adjacent to U.S. Geological Survey streamgaging stations in North Carolina. These data were collected during measurements of peak discharges that had recurrence intervals ranging from less than 2...

The National Water Quality Laboratory (NWQL) determined ammonium plus organic nitrogen (Kjeldahl nitrogen) by using semiautomated, block digester methods for filtered and whole-water samples from 1986 until October 1, 1991. During that time, phosphorus was determined by a persulfate digestion method. In 1991, projected increases in demand for both tests by the U.S. Geological Survey?s National Water-Quality Assessment Program led...

No abstract available....

During July, 1997, twenty four Schlumberger dc resistivity soundings were made in the Boulder watershed and adjacent areas (fig. 1). The objective of geophysical studies in the watershed is to map subsurface lithologic, structural and hydrologic features important in controlling possible ground water contamination from mining activities and for design...

Most of the Christian quadrangle is in the Porcupine Plateau; the northwestern part is in the southern Brooks Range, and the southern quarter is in the Yukon Flats. Outcrops of bedrock are poor or lacking, except in the Brooks Range. Although large valley glaciers have moved through the Porcupine Plateau,...

The U.S. Geological Survey has completed an integrated geologic and geophysical study of the Texas Springs syncline for the National Park Service with the intention of locating a new production water well near existing water-collection and distribution facilities. Subsurface information was required to determine which, if any, sites within the...