Showing papers in "Journal of Applied Geophysics in 1994"

TL;DR: In this article, the potential field tilt is defined in terms of the ratio of the first vertical derivative of a potential field to the horizontal gradient of the field, which has the property of being positive over a source and negative elsewhere.

TL;DR: In this article, a geoelectrical survey was conducted at a site along Highway 6 where it passes the coastal town of Provincetown and a sanitary landfill near Cape Cod.

TL;DR: In this paper, the authors combined application of these two methods is the most promising way to delineate accurately groundwater-bearing aquifers and to evaluate the quality of the water, which was tested during the feasibility study carried out under different hydrogeological conditions throughout Israel during August-September 1992.

TL;DR: In this paper, the groundwater contamination by a landfill, located on very porous and permeable formations, is assessed by both geophysical and hydrological techniques, and the overall results are integrated and discussed as well as the merits and disadvantages of the techniques used.

TL;DR: In this paper, a geostatistical analysis of semivariance, made on a series of more than 600 measurements, shows a spatially structured geophysical heterogeneity, both for the values of resistivity and for those of phase.

TL;DR: In this paper, the authors applied reflection seismics to ground-probing radar (GPR) reflection profiles in order to gain information about the geometry of inhomogeneities.

TL;DR: The results of a large scale exploration of an archaeological site by geophysical means are presented and discussed in this article, where resistivity prospecting is employed to detect the remnants of wall foundations in the place where the main urban complex of the ancient city once stood.

TL;DR: The magnetic susceptibility of ferrimagnetic pyrrhotite is determined empirically from the variation trend in a density-susceptibility diagram of pyrhotite-containing rocks as mentioned in this paper.

TL;DR: In this article, the authors demonstrate an automatic method for the construction of a resistivity cross-section using a new generation of regularised inversion methods, which attempt to overcome the problem of equivalence/non-uniqueness in EM sounding data by constructing the resistivity distribution with the minimum amount of structure that fits the data.

TL;DR: In this paper, a model for calculating the thermal conductivity of reservoir rocks as a function of mineral composition, porosity, fluid type, and temperature has been developed based on fabric theory and experimental data.

TL;DR: In this article, the US Geological Survey in cooperation with the National Drilling Company of Abu Dhabi is conducting a 4-year study of the fresh and slightly saline groundwater resources of the eastern Abu Dhabi Emirate, where the original field tapes from the vibroseis survey were reprocessed in an attempt to extract shallow subsurface information (depths less than 550 m).

TL;DR: A geoelectrical resistivity survey was carried out in the existing Kaffrein dam site, near the Dead Sea, Jordan, in order to investigate channel seepage and the hydrological conditions of the alluvial deposits in the upstream as well as downstream areas of the dam.

TL;DR: In this paper, the authors simulate steady state pressure and radon concentration fields in the ground surrounding a cylindrical building and show that the radon transport by advection and by diffusion strongly depends on the gas permeability of the underground.

TL;DR: In this article, the authors compare DC electrical soundings and electrostatic ones in order to establish the practicability of this new technique, and present solutions allowing to overcome technical measurement problems and to interpret the results by taking into account the effect of induced currents.

TL;DR: In this paper, resistivity profiling with three different array lengths, and ground-penetrating radar were used at the same time for the detection of solution cavities behind the concrete lining in a 2 km long part of a water delivery tunnel in Switzerland.

TL;DR: In the case of pyrrhotite, the remanent magnetisation carried by pyrhotite is readily reset by medium to low grade thermal events, but can be quite stable at ambient and slightly elevated temperatures as discussed by the authors.

TL;DR: In this article, a new concept, amplitude-direction plots, is introduced to separate features based on their combined amplitude and direction, and the developed statistical methods are employed to decide whether any significant secondary trends remain.

TL;DR: In this paper, the in-situ stress field can be applied both in planning most stable drilling trajectories and also in maximizing intersection of a wellbore with open, natural, and hydraulically-induced fractures in the reservoir.

TL;DR: Magnetic anomalies from four sites in Germany are described together with their interpretation based on magnetic modelling in this article, where the top of the source bodies are situated several hundred meters below the surface and Boreholes at all the sites enabled the identification of pyrhotite as the carrier of magnetization.

TL;DR: In this paper, ground probing radar (GPR) measurements have been made on laboratory concrete structures for detecting cavities or gravel pockets and for determining if they are filled with air or water.

TL;DR: In this paper, the authors present a new testing concept and analysis procedure based on a time sequence of wellbore electric conductivity logs, which provides the exact location and the outflow parameters (transmissivity, formation fluid conductivity) of flowing features (fractures, faults, layers) intercepted by the borehole.

TL;DR: In this article, the authors attempted to predict the underground temperature of the planned Gotthard railroad tunnel (NEAT), which will have a total length of 56 km with a maximum cover of 2500 m.

TL;DR: A tensor magnetotelluric test survey was carried out in the region of Santa Catarina, located in the Chalco sub-basin of the Mexico Basin this article.

TL;DR: In this article, the authors evaluate hydrogeological properties of the fjord delta aquifers with emphasis on the possibilities of abstracting saline groundwater for use in fish farming.

TL;DR: In this paper, a 60-fold seismic reflection profile was recorded using Vibroseis sources in the vicinity of the Buchans mine, and the resolution of the reflections was greatly improved by two processes: (1) the application of refraction static corrections, and (2) spectral balancing of the NMO-corrected CMP gathers over two octaves prior to stacking.

TL;DR: In this paper, a procedure for the estimation of the lithological description of the stratigraphical formation by wells is described; in this procedure the results of wireline measurements and a litho-facies database are combined.

TL;DR: In this paper, a project has been launched sponsored by the ENMOTEC GmbH, company in which the following geoelectric methods were applied: resistivity profiling, VLF and VES.

TL;DR: In this article, the authors assess the effect of the ray propagation model, the measurement errors, and the error functions on the resolving ability of algebraic algorithms and show that the maximum ray error function increases convergence gradients compared with the average error function and has higher probability of local minima.

TL;DR: The average indoor radon concentration in Swiss living rooms is about 60-70 Bq m−3, this corresponds to an annual dose of about 2.2 mSv.

TL;DR: In this article, a multimethod geophysical survey of a large sedimentary basin in the Kalahari desert, for the purpose of assessing its water resources, was carried out, using gravimetry, magnetometry and audio-magnetotellurics (AMT).