Showing papers in "Geoexploration in 1978"

TL;DR: In this paper, the Western Geological Company of America Service Mark (MED) was developed to aid the extraction of detailed reflectivity information from amplitude anomalies in reflection seismic recordings, which depends on accurate compensation for the combined effects of the source wavelet and earth filtering.

TL;DR: The fundamental problems in automatic recognition of seismic events are examined with particular emphasis on feature extraction and digital signal processing with the discussion of geophysical features.

TL;DR: In this paper, the authors reviewed the development of the normal-incidence reflection seismogram from a physical point of view and showed how the kepstrum relates to the fine-grain structure of the physical model.

TL;DR: In this paper, a method of obtaining the parameters (viz. the width, depth to the top and inclination of magnetic vector) of an infinitely dipping dike from its magnetic effect is proposed.

TL;DR: A simple algorithm which identifies earthquakes and times first arrivals using data from an array of single component seismometers is being studied, and would provide for the first time, an accurate objective data base for earthquake prediction research.

TL;DR: In this paper, a method for the numerical solution of the magnetostatic field problem of bodies with high susceptibility (k > 1 SI) is given, and the surface integral equation is solved numerically by means of the method of subsections for two different geometries: 3-dimensional bodies whose boundaries are approximated by rectangular planes aligned with the coordinate planes, and 2 1 2 -dimensional bodies, where the cross-section of the boundaries are oriented arbitrarily.

TL;DR: In this paper, a comparative study of the IP and apparent resistivity responses of Wenner, dipole dipole, pole dipole and pole pole arrays over a sheet-like target was made by means of scale model experiments, which allowed a qualitative comparison of the electrode arrays with respect to the amplitude and width of their anomalous response and evaluation of their relative depth penetration.

TL;DR: In this article, a class of homomorphic systems matched to the band-pass nature of seismic signals is discussed and improved and more reliable implementation algorithms are developed for the estimation of the earth impulse response.

TL;DR: In this article, a Fourier series approach has been employed to compute the time-domain electromagnetic response of earth-sections consisting of any number of subsurface horizontal layers and the complex mutual impedances, computed very accurately with the help of linear digital filter technique, corresponding to each Fourier component composing the excitation pulse have been summed to obtain timedomain response for horizontal coplanars and vertical coplanar loops systems.

TL;DR: In this article, a frequency-domain formalism for synthesizing normal incidence reflection seismograms for multilayered elastic and dissipative media is presented, where a solid friction model has been adopted that provides frequency-dependent absorption and velocity free from dispersion effects.

TL;DR: In this article, the tripotential technique with the Wenner configuration is preferred to other more traditional methods, and higher quality and more useful results are obtained in the city of Canavieiras, Bahia.

TL;DR: In this article, an iterative method was proposed to identify non-invertible seismic models under the assumption that the reflection coefficient sequence of the unknown (and desired) deep reflecting interfaces is not invertible.

TL;DR: The Datacomputer as discussed by the authors is a very large-capacity, centralized database management facility for distributed networks and was developed for the Advanced Research Projects Agency (ARPA) by CCA, and is currently available on the Arpanet.

TL;DR: Based on the decay characteristics, a total of 344 AEM-INPUT anomalies recorded in a multiparameter airborne geophysical survey over a part of Jhansi district (U.P.) India is studied and classified as good (38), medium (82) and poor (224) as discussed by the authors.

TL;DR: In this article, a method is developed for group velocity dispersion analysis of seismic surface waves using the instantaneous frequency estimator of Griffiths (1975) The inverse of a data-adaptive prediction error spectrum is contoured to give a high-resolution estimate of the group arrival time of a compact waveform.

TL;DR: In this paper, it was shown that the off-central sub-filter weights acquire cyclical values and remain finite as the number of sub-filters used is increased, however, the resulting inverse filter is infinitely long with significant weights all the way to infinity.

TL;DR: In this article, an interactive seismic processing system (ISPS) developed by Texas Instruments Incorporated was implemented on the PDP-15 Computer located at the Seismic Data Analysis Center in Alexandria, Virginia.

TL;DR: In this paper, a large area on the eastern margin of the Yilgarn Block was studied by interpreting aeromagnetic, radiometric and gravity data, and four major provinces were delineated: a western Archaean Yilgar province, dominantly granite/gneiss; a gneissic/migmatitic transition province; a Proterozoic granulitic province; and an eastern plutonic complex underneath a veneer of Eucla Basin Tertiary sediments.

TL;DR: In this paper, a method to investigate the secular equilibrium of natural U- and Th-series with gammaray spectroscopy has been developed, which has been applied to a study of the possible radiation inequilibrium of three different mineral samples using a Ge(Li)-detector, an “intrinsic” Ge-detector and a 4096-channel pulse-height analyzer.

TL;DR: In this paper, a comparison of the decay patterns of the transient magnetic field and the voltage values for 1. conducting sphere, 2. conducting cylinder, and 3. conducting and permeable sphere is made.