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At least 1,603 records · Page 89Linked to original sources
USGS1985

Geodetic accuracy of Landsat-4 Multispectral Scanner and Thematic Mapper data

EROS Data Center is evaluating the geodetic accuracy of Landsat-4 data from both the Multispectral Scanner (MSS) and Thematic Mapper (TM) processing systems. Geodetic accuracy is a measure of the precision of Landsat data registration to the Earth's figure. This paper describes a geodetic accuracy assessment of several MSS and TM scenes, based on the geodetic referencing information supplied on a standard Landsat 4 computer compatible tape.

Conference Paper↗
USGS1984

COORDINATION OF FEDERAL DIGITAL CARTOGRAPHIC ACTIVITIES.

Throughout the Federal Government, applications are emerging for spatial data bases that require digital cartographic data as a framework. This paper describes some major applications of spatial data in the Federal Government, and it discusses the extent to which these data needs are being coordinated. Efforts are outlined towards further coordination of digital cartographic data bases and production in the Federal Government.

Conference Paper↗
USGS1984

REMOTE-SENSING MINERAL DISCOVERIES IN THE MOJAVE DESERT OF CALIFORNIA.

As a result of remote sensing studies in the Mojave Desert of California three previously unknown stockwork molybdenum systems have been discovered. It is not known if economic deposits of molybdenum and associated minerals occur in these areas; there is, however, sufficient data to judge that these areas are worthy of further exploration. The purpose of this paper is to present case histories of two of these discoveries. These discoveries have been made from laboratory analyses of Landsat multispectral scanner images to map limonitic materials and from field reconnaissance to determine if the limonite is due to hydrothermal alteration. In those areas that seemed most promising, airborne spectrometer surveys were employed to mapped Al-OH minerals, and audio-magnetotelluric (AMT) and telluric-traversing surveys were performed to obtain information at depth.

Conference Paper↗
USGS1984

A//r//m//s AND SEISMIC SOURCE STUDIES.

This paper briefly summarizes some recent developments in studies of seismic source parameter estimation, emphasizing the essential similarities between mining-induced seismogenic-failure and naturally occurring, tectonically driven earthquakes. The root-mean-square acceleration, a//r//m//s, shows much promise as an observational measure of high-frequency ground motion; it is very stable observationally, is insensitive to radiation pattern, and can be related linearly to the dynamic stress differences arising in the faulting process. To interpret a//r//m//s correctly, however, requires knowledge of f//m//a//x, the high-frequency band-limitation of the radiated field of earthquakes. As a practical matter, f//m//a//x can be due to any number of causes, but an essential ambiguity is whether or not f//m//a//x can arise from source properties alone. The interaction of the aftershocks of the Oroville, California, earthquake illustrates how a//r//m//s stress drops may be connected to detailed seismicity patterns.

Conference Paper↗
USGS1988

Stochastic system identification in structural dynamics

Recently, new identification methods have been developed by using the concept of optimal-recursive filtering and stochastic approximation. These methods, known as stochastic identification, are based on the statistical properties of the signal and noise, and do not require the assumptions of current methods. The criterion for stochastic system identification is that the difference between the recorded output and the output from the identified system (i.e., the residual of the identification) should be equal to white noise. In this paper, first a brief review of the theory is given. Then, an application of the method is presented by using ambient vibration data from a nine-story building.

Conference Paper↗
USGS1988

Federal microcomputer software for urban hydrology

The purpose of this paper is to describe the development, availability, and general use of selected urban hydrology microcomputer software developed by: U.S. Soil Conservation Service (SCS); U.S. Army Corps of Engineers, Hydrologic Engineering Center (HEC); U.S. Environmental Protection Agency (EPA); and U.S. Geological Survey (USGS). The discussion is limited to software used for design and planning for urban stormwater flows.

Conference Paper↗
USGS1988

Predicting tidal currents in San Francisco Bay using a spectral model

This paper describes the formulation of a spectral (or frequency based) model which solves the linearized shallow water equations. To account for highly variable basin bathymetry, spectral solutions are obtained using the finite element method which allows the strategic placement of the computation points in the specific areas of interest or in areas where the gradients of the dependent variables are expected to be large. Model results are compared with data using simple statistics to judge overall model performance in the San Francisco Bay estuary. Once the model is calibrated and verified, prediction of the tides and tidal currents in San Francisco Bay is accomplished by applying astronomical tides (harmonic constants deduced from field data) at the prediction time along the model boundaries.

Conference Paper↗
USGS1988

Calibration of water-velocity meters

The U.S. Geological Survey, Department of the Interior, as part of its responsibility to appraise the quantity of water resources in the United States, maintains facilities for the calibration of water-velocity meters at the Gulf Coast Hydroscience Center's Hydraulic Laboratory Facility, NSTL, Mississippi. These meters are used in hydrologic studies by the Geological Survey, U.S. Army Corps of Engineers, U.S. Department of Energy, state agencies, universities, and others in the public and private sector. This paper describes calibration facilities, types of water-velocity meters calibrated, and calibration standards, methods and results.

Conference Paper↗
USGS1986

ESTIMATION OF URBAN STORM-RUNOFF LOADS.

The United States was divided into three regions, on the basis of mean annual rainfall, to decrease the variability in storm-runoff constituent loads and to improve regression relations with basin and climatic characteristics. Multiple-regression analyses, in progress, are being refined to determine the best regression models for each of the storm-runoff constituent loads in each of the three regions. These techniques, when finalized, can be used to estimate storm-runoff constituent loads for gaged and ungaged urban watersheds. The preliminary standard errors of estimate for five constituents examined to date ranged from 54 to 223 percent, and the coefficients of determination (r**2) ranged from 0. 39 to 0. 94. Total storm rainfall and total contributing drainage area appear to be the most significant independent variables in the regression models. This paper is a progress report on preliminary results of estimating storm-runoff constituent loads for ungaged watersheds.

Conference Paper↗
USGS1986

LIMESTONE AND MARBLE DISSOLUTION BY ACID RAIN: AN ONSITE WEATHERING EXPERIMENT.

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 surface. A statistically significant linear relation has been found between carbonate-rock surface-recession rate and hydrogen ion loading to the rock surface.

Conference Paper↗
USGS1986

STRONG-MOTION INSTRUMENTATION OF STRUCTURES IN CHARLESTON, SOUTH CAROLINA AND ELSEWHERE.

Instrumentation of structures is part of earthquake hazard mitigation program of many institutions, including the United States Geological Survey (USGS). The USGS Strong-Motion Instrumentation of Structures Program is designed to complement other programs and to implement its own, within budget and other constraints. This paper reviews the overall national effort, cites examples of structures implemented and describes progress made to date. A recent example of instrumentation of an eight-story building in Charleston, South Carolina is documented.

Conference Paper↗
USGS1986

ANALYSIS OF THE U. S. GEOLOGICAL SURVEY STREAMGAGING NETWORK.

This paper summarizes the results from the first 3 years of a 5-year cost-effectiveness study of the U. S. Geological Survey streamgaging network. The objective of the study is to define and document the most cost-effective means of furnishing streamflow information. In the first step of this study, data uses were identified for 3,493 continuous-record stations currently being operated in 32 States. In the second step, evaluation of alternative methods of providing streamflow information, flow-routing models, and regression models were developed for estimating daily flows at 251 stations of the 3,493 stations analyzed. In the third step of the analysis, relationships were developed between the accuracy of the streamflow records and the operating budget. The existing streamgaging networks in four Districts were further analyzed to determine the impacts that satellite telemetry would have on the cost effectiveness. Satellite telemetry was not found to be cost effective on the basis of hydrologic-data collection alone, given present cost of equipment and operation.

Conference Paper↗
USGS1986

VISCOPLASTIC FLUID MODEL FOR DEBRIS FLOW ROUTING.

This paper describes how a generalized viscoplastic fluid model, which was developed based on non-Newtonian fluid mechanics, can be successfully applied to routing a debris flow down a channel. The one-dimensional dynamic equations developed for unsteady clear-water flow can be used for debris flow routing if the flow parameters, such as the momentum (or energy) correction factor and the resistance coefficient, can be accurately evaluated. The writer's generalized viscoplastic fluid model can be used to express such flow parameters in terms of the rheological parameters for debris flow in wide channels. A preliminary analysis of the theoretical solutions reveals the importance of the flow behavior index and the so-called modified Froude number for uniformly progressive flow in snout profile modeling.

Conference Paper↗
USGS1986

PERFORMANCE OF AN EARTHQUAKE EXCITED ROOF DIAPHRAGM.

The objective of this paper is to study the earthquake performance of the roof diaphragm of the West Valley College gymnasium in Saratoga, California through a complete set of acceleration records obtained during the 24 April 1984 Morgan Hill Earthquake (M equals 6. 1). The roof diaphragm of the 112 ft. multiplied by 144 ft. rectangular, symmetric gymnasium consists of 3/8 in. plywood over tongue-and-groove sheathing attached to steel trusses supported by reinforced concrete columns and walls. Three sensors placed in the direction of each of the axes of the diaphragm facilitate the evaluation of in-plane deformation of the diaphragm. Other sensors placed at ground level measure vertical and horizontal motion of the building floor, and consequently allow the calculation of the relative motion of the diaphragm with respect to the ground level.

Conference Paper↗
USGS1989

High-resolution two dimensional advective transport

The paper describes a two-dimensional high-resolution scheme for advective transport that is based on a Eulerian-Lagrangian method with a flux limiter. The scheme is applied to the problem of pure-advection of a rotated Gaussian hill and shown to preserve the monotonicity property of the governing conservation law.

Conference Paper↗
USGS1989

Recent progress on hydrodynamic modeling of San Francisco Bay, California

A hydrodynamic modeling study of the effects of freshwater inflow on circulation and mixing in San Francisco Bay has been underway since 1985. This paper describes the multidimensional hydrodynamic models being used on the study and review recent progress with their applications. Particular modeling considerations for San Francisco Bay and future modeling plans are discussed.

Conference Paper↗
USGS1989

Regionalization of flood characteristics

Regionalization procedures are used to transfer flood characteristics from gaged to ungaged locations. These procedures are an extension of the gaging network that allows planners and designers to make estimates of flood frequency at ungaged sites of interest. The U.S. Geological Survey has a long time involvement in the development of these regionalization procedures. This paper describes the evolution of these regionalization procedures from the index-flood procedure used in the 1940's to the multiple regression procedure based on generalized least squares that is currently being used.

Conference Paper↗
USGS1987

DISTRIBUTED GROUND-WATER DATA BASE OF THE U. S. G. S.

During the past 20 years, the ground-water data base of the U. S. Geological Survey has evolved from paper files in local offices, to a national data base on a central mainframe computer, to a distributed data base on a network of 49 minicomputers throughout the United States. Users in local offices have easy, inexpensive access to the distributed data base. The distributed data base has caused some problems in data management but has increased the overall quality of the data base.

Conference Paper↗