Conference Papers

No abstract available 

Changes in salinity and nitrate concentration in groundwater and surface water in the semiarid Arkansas River valley of southeastern Colorado, USA were related primarily to irrigation practices. Water is applied to fields by flood irrigation through ditches and furrows. Irrigation water is derived in nearly equal amounts from surface water and groundwater pumped from the shallow alluvial aquifer.

The collapse of the north face of Mount St. Helens on May 18, 1980, and the debris avalanche that resulted blocked outflow from Spirit Lake and Coldwater and South Fork Castle Creeks. Spirit Lake began to increase in size and lakes began to form in the canyons of Coldwater and South Fork Castle Creeks. Coldwater and Castle Lakes would have overtopped their respective blockages in late 1981 or earl

In this paper the authors describe an experimental research program, conducted in conjunction with the National Acidic Precipitation Assessment Program (NAPAP), to quantify acid-rain damage to commercial and cultural carbonate-rock resources. Initial results of this experiment show that carbonate-rock dissolution and associated surface recession increase with increasing acid deposition to the rock

The Charleston, South Carolina, area offers a unique opportunity to conduct studies that give insight into the implementation of policy for long-term earthquake preparedness at the local level. Research by Greene and Gori documented the low state of preparedness in 1981. Recent studies show that earthquake preparedness activities are now occurring in Charleston. Since 1981, increased national atte

MAPGEN is a software system that facilitates production of cartographic displays in the research and production environment. The system generates a set of metagraphic overlays of application-defined geographical information that can be aggregated in any combination for display without reprocessing the original data. An overview of the control files, available cartographic projections, graphic attr

In 1984, the U.S. Geological Survey conducted a detailed geologic analysis of two nuclear test craters at Enewetak Atoll, Marshall Islands, on behalf of the Defense Nuclear Agency. A multidisciplinary task force mapped the morphology, surface character, and subsurface structure of two craters, OAK and KOA. The field mapping techniques include echo sounding, sidescan sonar imaging, single-channel a

Thirteen natural frequencies of a concrete arch dam (Monticello Dam near Sacramento, California) have been identified by using a dynamic testing method which employs an air gun firing in the reservoir as the excitation source. These vibrations modes are determined from the peak responses in the Fourier amplitude spectra of the free-vibration data recorded at three crest locations using three-compo

No abstract available 

A procedure for calculating the quantities of normative minerals and kerogen in Colorado oil shale was developed and used to analyze a sequence of sodium-rich oil shales in a core hole near the depocenter of the Piceance Creek Basin in northwestern Colorado. The sequence of oil shales was found to average 48. 1 weight percent carbonate minerals, 32. 5 percent silicate minerals, 1. 9 percent pyrite

No abstract available.

A seismological stochastic model for earthquake ground-motion description is presented. Seismological models are based on the physical properties of the source and the medium and have significant advantages over the widely used empirical models. The model discussed here provides a convenient form for estimating structural response by using random vibration theory. A commonly used random process fo