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Research about Virginia, West Virginia

Source-linked reports with geographic coverage including Virginia, West Virginia.

At least 37 records · Page 2Linked to original sources
USGS2008

Bedrock structural controls on the occurrence of sinkholes and springs in the Northern Great Valley Karst, Virginia and West Virginia

Recent geologic mapping at a scale of 1:24,000 has enabled a qualitative correlation of the occurrence of springs and sinkholes with bedrock structures and ground-water conditions in the northern Great Valley of Virginia and West Virginia. Sinkholes tend to be concentrated in zones of faulting, local minor folding, and clustered within susceptible bedrock units at the noses and axes of large plunging folds. Alignment of sinkholes mainly occurs along strike of bedding. Enhanced rock solution and conduit formation correlates with carbonate units of greater limestone purity and finer grain size, suggesting some lithologic control on karst formation. In addition, there is an apparent topographic correlation, with sinkholes usually formed in elevated and flat (<5 degrees slope) areas, as well as frequent sinkhole occurrence proximal to entrenched surface streams. Density of sinkhole occurrence tends to increase in areas where water-table fluctuations are large. Large perennial springs occur along faults, and may lie above base level streams indicating upward flow gradients particularly where cross-strike faults and joints intersect bedding planes and strike-parallel faults. Sinkhole formation also frequently occurs in areas proximal to entrenched surface streams, reflecting subsequent vadose-zone modification and excavation of sediment-filled conduits where downward ground-water flow gradients are most steep. Geologic evidence indicates that deep karst development may have taken place by rising fluids under confined (hypogenic) conditions in the distant geologic past in this region.

Virginia, West Virginia↗
USGS2008

Simulation of ground-water flow in the Shenandoah Valley, Virginia and West Virginia, using variable-direction anisotropy in hydraulic conductivity to represent bedrock structure

Ground-water flow was simulated using variable-direction anisotropy in hydraulic conductivity to represent the folded, fractured sedimentary rocks that underlie the Shenandoah Valley in Virginia and West Virginia. The anisotropy is a consequence of the orientations of fractures that provide preferential flow paths through the rock, such that the direction of maximum hydraulic conductivity is oriented within bedding planes, which generally strike N30 deg E; the direction of minimum hydraulic conductivity is perpendicular to the bedding. The finite-element model SUTRA was used to specify variable directions of the hydraulic-conductivity tensor in order to represent changes in the strike and dip of the bedding throughout the valley. The folded rocks in the valley are collectively referred to as the Massanutten synclinorium, which contains about a 5-km thick section of clastic and carbonate rocks. For the model, the bedrock was divided into four units: a 300-m thick top unit with 10 equally spaced layers through which most ground water is assumed to flow, and three lower units each containing 5 layers of increasing thickness that correspond to the three major rock units in the valley: clastic, carbonate and metamorphic rocks. A separate zone in the carbonate rocks that is overlain by colluvial gravel - called the western-toe carbonate unit - was also distinguished. Hydraulic-conductivity values were estimated through model calibration for each of the four rock units, using data from 354 wells and 23 streamflow-gaging stations. Conductivity tensors for metamorphic and western-toe carbonate rocks were assumed to be isotropic, while conductivity tensors for carbonate and clastic rocks were assumed to be anisotropic. The directions of the conductivity tensor for carbonate and clastic rocks were interpolated for each mesh element from a stack of 'form surfaces' that provided a three-dimensional representation of bedrock structure. Model simulations were run with (1) variable strike and dip, in which conductivity tensors were aligned with the strike and dip of the bedding, and (2) uniform strike in which conductivity tensors were assumed to be horizontally isotropic with the maximum conductivity direction parallel to the N30 deg E axis of the valley and the minimum conductivity direction perpendicular to the horizontal plane. Simulated flow penetrated deeper into the aquifer system with the uniform-strike tensor than with the variable-strike-and-dip tensor. Sensitivity analyses suggest that additional information on recharge rates would increase confidence in the estimated parameter values. Two applications of the model were conducted - the first, to determine depth of recent ground-water flow by simulating the distribution of ground-water ages, showed that most shallow ground water is less than 10 years old. Ground-water age distributions computed by variable-strike-and-dip and uniform-strike models were similar, but differed beneath Massanutten Mountain in the center of the valley. The variable-strike-and-dip model simulated flow from west to east parallel to the bedding of the carbonate rocks beneath Massanutten Mountain, while the uniform-strike model, in which flow was largely controlled by topography, simulated this same area as an east-west ground-water divide. The second application, which delineated capture zones for selected well fields in the valley, showed that capture zones delineated with both models were similar in plan view, but differed in vertical extent. Capture zones simulated by the variable-strike-and-dip model extended downdip with the bedding of carbonate rock and were relatively shallow, while those simulated by the uniform-strike model extended to the bottom of the flow system, which is unrealistic. These results suggest that simulations of ground-water flow through folded fractured rock can be constructed using SUTRA to represent variable orientations of the hydraulic-conductivity tensor and produce a

Virginia, West Virginia↗
USGS2006

Digital data set of orchards where arsenical pesticides were likely used in Clark and Frederick Counties, Virginia, and Berkeley and Jefferson Counties, West Virginia

This Fact Sheet provides information on a digital data set that identifies orchard areas under cultivation between the 1920s and 1960s in Clarke and Frederick Counties, Virginia and Berkeley and Jefferson Counties, West Virginia. The apple orchards in these areas likely used arsenical pesticides during this time. The digital data set can be used in a geographic information system (GIS) to identify where elevated arsenic and lead concentrations may be present in soils. The digital data set, the associated metadata, and the related files are available on the World Wide Web at http://pubs.usgs.gov/of/2006/1330/shapefile/.

Virginia, West Virginia↗
USGS2006

Digital data set of orchards where arsenical pesticides were likely used in Clark and Frederick Counties, Virginia, and Berkeley and Jefferson Counties, West Virginia

This data set shows orchard locations in Clarke and Frederick Counties, Virginia, and Berkeley and Jefferson Counties, West Virginia where arsenical pesticides have likely been used. The orchard locations (fig. 1) were compiled from aerial photos and topographic maps for the time period of extensive use of arsenical pesticides between the 1920s and 1960s. An orchard's presence in this data set does not necessarily indicate the use of arsenical pesticides on that site or that elevated arsenic and metal concentrations are present. Arsenical pesticides may have been used on part, or none, of the land; furthermore, the land may have been remediated and may no longer contain elevated arsenic and metal concentrations in the soil.

Virginia, West Virginia↗
USGS1993

Introduction: Geomorphic studies of the storm and flood of November 3-5, 1985, in the upper Potomac and Cheat River basins

The heavy rains of November 3-5, 1985, produced record floods and extensive landsliding in the Potomac and Cheat River basins in West Virginia and Virginia (pl. 1). Although rainfall intensity was moderate, the storm covered a very large area and produced record floods for basins in the size range of 1000-10,000 km 2 . In addition, thousands of landslides were triggered on slopes underlain by shale bedrock. The total social cost of the storm amounted to 70 lives lost and an estimated $1.3 billion in damage to homes, businesses, roads, and productive land in West Virginia and Virginia (Federal Emergency Management Agency (FEMA) 1985a, b). These extreme costs were incurred despite the fact that the affected area is sparsely populated. To understand the origins and geomorphic effects of the 1985 storm, studies were undertaken by the U.S. Geological Survey, University of Maryland, West Virginia University, Cornell University, University of Virginia, The Johns Hopkins University, and Carleton College. Personnel were also consulted from the National Weather Service, Nuclear Regulatory Commission, U.S. Army Corps of Engineers, Soil Conservation Service, and Interstate Commission on the Potomac River basin. This cooperative effort serves to document the effects of the storm as an example of an extreme geomorphic event in the central Appalachian Mountains. The following chapters comprise observations and preliminary analyses for some of the observed phenomena. Subsequent publications by the contributors to this volume will expand the scope of this research.

Virginia, West Virginia↗
USGS1989

Slope movements triggered by heavy rainfall, November 3–5, 1985, in Virginia and West Virginia, U.S.A.

Study of slope movements triggered by the storm of November 3–5, 1985, in the central Appalachian Mountains, U.S.A., has helped to define the meteorologic conditions leading to slope movements and the relative importance of land cover, bedrock, surficial geology, and geomorphology in slope movement location. This long-duration rainfall at moderate intensities triggered more than 1,000 slope movements in a 1,040-km 2 study area. Most were shallow slips and slip-flows in thin colluvium and residuum on shale slopes. Locations of these failures were sensitive to land cover and slope aspect but were relatively insensitive to topographic setting. A few shallow slope movements were triggered by the same rainfall on interbedded limestone, shale, and sandstone. Several large debris slide-avalanches were triggered in sandstone regolith high on ridges in areas of the highest measured rainfall. Most of these sites were on slopes that dip 30 to 35° and lie parallel to bedding planes, presumably the sites of least stability.

Virginia, West Virginia↗
USGS1987

Preliminary results from a study of natural slope failures triggered by the storm of November 3.5.1985, Germany Valley, West Virginia and Virginia: Chapter 4 in Landslides of eastern North America

During the first five days of November 1985, a low-pressure system in the Ohio River valley combined with a low-pressure system referred to as Tropical Storm Juan to produce heavy rainfall in the Potomac, James, and Rappahannock River basins. Severe flooding accompanied the rainfall; 43 lives were lost and the flood was estimated to be the most expensive natural disaster of 1985 in the United States (Scatena, 1986). The rainfall also triggered many slope failures. An especially large concentration of slope failures was associated with an area of moderate rainfall centered in the Germany Valley in Pendleton County, West Virginia (fig. 4.1A ). This report describes some preliminary results from our continuing research into the geological and meteorological controls on the distributions of slope failures in the Germany Valley area. The Germany Valley is the first major anticlinal valley in the Valley and Ridge province east of the Allegheny structural front (Diecchio, 1986). Our interest is focused on the portion from near Mouth of Seneca, West Virginia, in the Onego 7 .5-minute quadrangle, to near Mill Gap, Virginia, in the Mustoe 7.5-minute quadrangle (patterned in figs. 4.1 and 4.2). This area was a natural experiment for studying the effects of the storm because rainfall varied systematically from southwest to northeast along the valley, while bedrock lithology and structure are nearly constant. Furthermore, variation of rock types across the valley allows comparisons among lithologies at given levels of precipitation. The valley is floored by Ordovician carbonates of the Trenton, Black River, and St. Paul Groups and shales of the Martinsburg (Reedsville) Shale. The ridges are formed by sandstones of the Tuscarora and Oswego Sandstones, and the Juniata formation. The southwestern quarter of the valley is drained by Back Creek of the James River basin, and the remainder of the valley drains north and west to the North Fprk of the South Branch Potomac River.

Virginia, West Virginia↗
USGS1975

Applications of remote sensing to structural interpretations in the southern Appalachians

Remote sensing is the technology of studying distant objects by measuring and recording energy from one or more segments of the electromagnetic spectrum. Imaging sensors which operate from medium- and high-altitude aircraft or from spacecraft can provide a synoptic view of large areas and of surface phenomena not evident in the field. Image-acquiring systems and instruments have been designed to partially automate data collection and to reduce the time devoted to analysis, information extraction, and detection of changes of surface phenomena. Among these phenomena are the surface distribution of heat, moisture, snow, water, vegetation, and cultural features. When coupled with ancillary data, including field surveys, sensor data provide useful information for the recognition and mapping of regional structure, jointing patterns, drainage patterns, fault and fracture traces, and rock types. The recognition of several major linear surface features, two of which proved to be traces of previously unrecognized faults (the Canebrake and the Coeburn faults) in the Appalachian Plateaus, demonstrates the pragmatic application of aircraft and spacecraft remote sensing to geological investigations in the Appalachians.

Virginia, West Virginia↗
USGS1974

Sandstone distribution patterns in the Pocahontas Formation of southwest Virginia and southern West Virginia

The Pocahontas Formation is a clastic wedge of sandstone, siltstone, shale, coal, and underclay that is transitional between underlying marine strata of Mississippian age and overlying continental beds of Pennsylvanian age. It attains a maximum thickness of 750 ft. at the southeastern edge of the Appalachian coal field and thins northwestward by the tonguing out of lower beds and by the truncation of upper beds at an overlying unconformity. Sandstone, which composes about 70 percent of the formation, occurs in lenticular bodies that have two distinct distribution patterns—lobate and linear—of contrasting orientation and composition. The lobate bodies are elongate to the northwest and contain sandstone having a quartz content of about 50 to 65 percent. Within a lobe, thickness lines show a northwestward bifurcating pattern similar to the pattern of channels in an alluvial distributary system of a modern delta. Laterally, lobate bodies merge to form northwestward-thinning sandstone wedges as much as 300 ft. thick. The linear pattern is shown by 3- to 8-mi.-wide sandstone lenses that extend north-northeast for about 45 mi. They are near the distal ends of the lobate sandstone and consist of 0 to 140 ft. of relatively pure quartzose sandstone. The well-washed character and orientation of the linear bodies, normal to the lobate bodies, indicate a barrier-bar origin. These sediment distribution patterns show that the Pocahontas Formation was deposited mainly in deltaic complexes built out from the southeast during marine regression to the northwest. Brief periods of transgression and stable shoreline conditions are recorded by tongues of marine strata and by the barrier bars.

Virginia, West Virginia↗