Open File Reports
Permanent URI for this collection
Browse
Browsing Open File Reports by Author "Jordan, R.R."
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Geologic Field Trips In Delaware(Newark, DE: Delaware Geological Survey, University of Delaware, 1977-05) Benson, R.N.; Hahn, W.F.; Jordan, R.R.; Pickett, T.E.; Talley, J.H.; Thompson, A.M.; Woodruff, K.D.The information contained in this Guidebook was compiled on the occasion of the Annual Meeting of the Association of American State Geologists held in Delaware in June 1977. The Delaware Geological Survey is pleased to have been selected to host this national meeting. The field trip logs were designed to familiarize geologists from across the United States with basic features of Delaware's geology and resources. We have also sought to identify some points of historical and cultural interest that may help the visitor become familiar with our State. Experience has shown that field guides retain their usefulness beyond the event that they initially served. They may assist classes, other groups, and individuals seeking additional information about their physical environment. Therefore, this Guidebook has been published as an Open File Report for public distribution. All users of this information are urged to exercise caution, especially at rock faces and along waterways, and to obtain specific permission for visits from landowners where necessary.Item Guidebook: Columbia Deposits Of Delaware(Newark, DE: Delaware Geological Survey, University of Delaware, 1976-05) Jordan, R.R.; Talley, J.H.The Columbia sediments of Delaware cover almost all of the surface of the Coastal Plain portion of the State. A major unconformity separates these predominantly sandy materials from the underlying rocks of the Coastal Plain. As it includes the materials closest to the surface in most places, the Columbia has great practical importance in Delaware. In addition to the morphology and soils which are largely dictated by the Columbia, it holds about 90 percent of the State's groundwater supplies, is the geologic foundation for most construction, and yields essentially all of the sand and gravel mined here.Item A Numerical Indicator Of Water Conditions For Northern Delaware(Newark, DE: Delaware Geological Survey, University of Delaware, 1982-05) Jordan, R.R.; Woodruff, K.D.Numerical indicators, or indices, are widely used to measure the status of complex relationships. As such, indices have become accepted by researchers and the public in such disparate fields as economics, air quality, and weather. In this paper we explore the formulation of an indicator of water conditions in northern Delaware, propose formulas that may be applicable, and test those proposals against long-term records of basic data. The need for a simple indicator of water supply conditions in Delaware, and especially in New Castle County, has become increasingly apparent. The Delaware River Basin Commission (DRBC) has applied an index to the Delaware River Basin, which includes a portion of Delaware. The Governor's Drought Advisory Committee has sought an objective means of determining when water supply conditions might warrant conservation measures. Discussions of the subject have also been held within the State Comprehensive Water Management Committee. We are pleased to acknowledge the constructive comments of these groups and of other colleagues with whom we have discussed this work. George R. Phillips of the Delaware Department of Natural Resources and Environmental Control (DNREC) was especially helpful in analyzing the practical implications of using the index presented in this paper. John R. Mather, Delaware State Climatologist, provided Palmer Drought Severity Index values with the cooperation of the National Weather Service. This report was reviewed by Richard N. Benson and John H. Talley of the Delaware Geological Survey (DGS).Item Preliminary Report On Seismic Events In Northern Delaware(Newark, DE: Delaware Geological Survey, University of Delaware, 1972-04) Jordan, R.R.; Pickett, T.E.; Woodruff, K.D.Earthquakes are an unfamiliar phenomenon in Delaware. Because of the great public and scientific interest in the seismic events that have recently affected northern Delaware, this Open File Report has been prepared to present currently available information concerning the earthquakes and the investigation pursued by the Delaware Geological Survey. This is not a final scientific explanation of the events. To many persons it is shocking to realize that the earth that they regard as stable is, in fact, an active body. The present earth is a product of 4.5 billion years of history, during which time most geologic forces have acted so slowly as to be almost imperceptible. Therefore, sudden movements are disturbing. Earthquakes are the vibrations caused by relatively sudden slippage of deeply buried rocks. Earthquakes occur in a vast range of sizes; many are too small to be felt and others cause great damage. The events in Delaware that are described on these pages were relatively small and, although they warrant further study, which may lead to some precautionary measures, they do not represent cause for alarm.Item Preliminary Report On The Earthquake Of February 28, 1973(Newark, DE: Delaware Geological Survey, University of Delaware, 1973-04) Woodruff, K.D.; Jordan, R.R.; Pickett, T.E.This report has been prepared to fill an immediate need for information on the earthquake that affected northern Delaware on February 28, 1973. Public interest in seismic events has grown in the past two years because of a series of small, local events (Jordan et al., 1972) and has been heightened considerably by the event described in this report. Various stresses on and within the earth lead to periodic adjustments or changes by the rocks making up the earth's crust. Many changes are too slow or small to be measured within a human lifetime, but earthquakes can be a very perceptible phenomenon, expressing more rapid adjustment. Indeed, earthquakes in many areas of the world are a serious geologic hazard and a threat to life and property. Thus, it must be recognized that the earth is a dynamic body and its processes are not bound to the convenience of man.