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Walter L. Anderson

Publications and source records attributed to Walter L. Anderson.

25 records · Page 2Linked to original sources
USGS1978

Interpretation of electromagnetic extra-low-frequency soundings in the Randsburg, California, Known Geothermal Resource Area

An electromagnetic (EM) controlled source survey was made during the period Nov. 30, 1977, to Dec. 13, 1977, in the Randsburg, California, Known Geothermal Resource Area (KGRA). This report summarizes the observed extra-low-frequency (ELF) data and least squares interpretation using a computer program developed by Anderson (1977). The results are given in tabular form along with observed and calculated amplitude and phase plots. In addition, one vertical electrical sounding (VES) was obtained and a graphical solution is included via a Schlumberger inversion program developed by Zohdy (1973).

California↗
USGS1975

Improved digital filters for evaluating Fourier and Hankel transform integrals

New algorithms are described for evaluating Fourier (cosine, sine) and Hankel (J 0 ,J 1 ) transform integrals by means of digital filters. The filters have been designed with extended lengths so that a variable convolution operation can be applied to a large class of integral transforms having the same system transfer function. A f' lagged-convolution method is also presented to significantly decrease the computation time when computing a series of like-transforms over a parameter set spaced the same as the filters. Accuracy of the new filters is comparable to Gaussian integration, provided moderate parameter ranges and well-behaved kernel functions are used. A collection of Fortran IV subprograms is included for both real and complex functions for each filter type. The algorithms have been successfully used in geophysical applications containing a wide variety of integral transforms

Report↗
USGS1969

Weighted triangulation adjustment

The variation of coordinates method is employed to perform a weighted least squares adjustment of horizontal survey networks. Geodetic coordinates are required for each fixed and adjustable station. A preliminary inverse geodetic position computation is made for each observed line. Weights associated with each observed equation for direction, azimuth, and distance are applied in the formation of the normal equations in-the least squares adjustment. The number of normal equations that may be solved is twice the number of new stations and less than 150. When the normal equations are solved, shifts are produced at adjustable stations. Previously computed correction factors are applied to the shifts and a most probable geodetic position is found for each adjustable station. Pinal azimuths and distances are computed. These may be written onto magnetic tape for subsequent computation of state plane or grid coordinates. Input consists of punch cards containing project identification, program options, and position and observation information. Results listed include preliminary and final positions, residuals, observation equations, solution of the normal equations showing magnitudes of shifts, and a plot of each adjusted and fixed station. During processing, data sets containing irrecoverable errors are rejected and the type of error is listed. The computer resumes processing of additional data sets.. Other conditions cause warning-errors to be issued, and processing continues with the current data set.

Open-File Report↗