Showing papers in "Geoexploration in 1984"

TL;DR: In this paper, the authors present a different representation, in which frequency shifts are replaced by dilations, and the resulting "voice transform" and "cycle-octave transform" are briefly described from the mathematical point of view and illustrated by numerical examples.

TL;DR: This work gives an overview of the cluster analysis and pattern recognition methods and performs hierarchical clustering on a small amount of data for reducing the feature set to an orthogonal one.

TL;DR: In this paper, an empirical function between electrical transverse resistances of an aquifer, corrected for the effect of their porewater resistivities and corresponding hydraulic transmissivities, has been found.

TL;DR: In this article, the results of a self-potential survey carried out in a coastal area of southern Italy where an upward water flow from an aquifer was manifested by the presence of some springs are presented.

TL;DR: In this article, the authors deal with the general subject of the linear system behavior of material media that have dispersive electrical properties and the corresponding time domain or transient response characteristics are also considered in the context of the induced polarization properties of the medium.

TL;DR: In this article, a borehole-to-borehole seismic system using piezoelectric transducers as active elements has been developed and used to investigate the geology at a test site located near Bell's Corners, Ontario.

TL;DR: In this paper, the detection of water flow in boreholes of the Canadian Shield is described, where the authors use temperature measurements at depth intervals of as coarse as 3 m to estimate flow rates or velocities.

TL;DR: In this paper, the depth dependence of the radon concentration in the soil gas has been studied with cellulose nitrate plastic detectors with the inverted cup technique, and the half length is found to be a function of the depth of the soil and the soil type.

TL;DR: An effective sequential algorithm is presented that employs an autoregressive modeling of the data and a generalized likelihood ratio test to detect the significant statistical changes in the waveform.

TL;DR: In this paper, a method for calculating mise-a-la-masse anomalies based on the assumption that each conducting body of the model is at its own constant potential is described.

TL;DR: In this paper, a tree classification method is proposed for the detection of bright spots in seismic signals. But, it is only used to detect bright spots if one of three hypotheses is satisfied.

TL;DR: In this article, self-potential (SP) and resistivity measurements were carried out in parts of the gneissic and khondalite belt of the Balangir district, Orissa, India to locate graphite deposits.

TL;DR: Affinity is a hierarchical clustering technique that can be used to segment waveforms as part of a syntactic (or structural) pattern recognition algorithm and it does not require any preset thresholds.

TL;DR: In this article, a detailed comparison between the hydraulic conductivity and resistivity, respectively, and the character of fractures in the core and the borehole wall is made to get a better understanding of the influence of fractures on resistivity and permeability.

TL;DR: In this paper, a multichannel borehole hydrophone array has been used to detect open fractures and rock property changes circumjacent to deep boreholes in granitic rock.

TL;DR: In this paper, a relationship between the magnetic susceptibility and the lithology of the cores has been established, based on the results of five boreholes measuring a total length of 2.8 km.

TL;DR: In this article, the authors describe the use of magnetic, electromagnetic, electric, and seismic measurements for the investigations of prospective sites for radioactive waste disposal in Sweden, where 7-10 deep boreholes are used to provide data on temperature, salinity, and gamma ray.

TL;DR: In this article, a wide-spacing multiple-electrode down-hole IP system has been developed for field applications, which can be used to detect targets narrowly missed by drilling, and to provide information on intersected mineralisation.

TL;DR: The concept of disposal of nuclear fuel wastes in igneous plutonic rocks is being assessed in the Canadian Nuclear Fuel Waste Management Program as discussed by the authors, but the decision on whether to implement this concept will be made only sometime after 1991.

TL;DR: In this paper, a thresholded and filled display called a "quadragram" is used to display the instantaneous envelope, phase and frequency of a seismic feature, and median filtering is applied to the display.

TL;DR: In this article, the results of shallow seismic reflections obtained with a downhole propane-oxygen detonator as a seismic source are presented, and a methodology, called ABO method, for computing static corrections quickly and accurately is discussed.

TL;DR: In this article, the estimation of the reflection coefficients and the source wavelet is studied in the context of reflection seismology, and different algorithms are presented to solve the problem, after some simple considerations on the concrete case.

TL;DR: In this paper, a method for converting DC-dipole resistivity sounding field data to an equivalent Schlumberger set has been described, and it has been shown that only six weights for the radial dipole and seven weights for perpendicular dipole are necessary for the transformation.

TL;DR: This work uses subspace representation for an instant signal analysis on the one hand and to represent a specific shape of a seismic event by using a low pass filtering on the other hand.

TL;DR: This approach, and the concerns (1)–(4) are especially relevant for the performance enhancement of a number of acoustic signal classification systems (e.g., seismic exploration, intrusion detection, sonar).

TL;DR: In this paper, the mean-squared error versus signal-to-noise ratio (SNR) of four estimators of instantaneous phase were compared and the adaptive estimators were found to be more accurate with the Kalman method being the best.