摘要:

AbstractAn apparatus is described for the measurement of Young's modulus,E, and the energy loss per cycle, ΔW/W,of small beam‐shaped rock samples, over the frequency range 2 to 40 c/s. Results are given for seven sedimentary and two igneous types of rock. An increase of between 1 % and 3 % inE,and of up to 100 % in ΔW/W,occurred over this range. Experiments on rocks containing moisture showed a decrease in the magnitude ofE(at2c/s), an increased frequency variation ofE,and a greater and almost linear increase of ΔW/Wwith frequency. The effect of oil was similar except that the magnitude ofEat2c/s was unaffected. It is suggested that the moisture and oil results are due to viscous movements of fluid through the pores in the rock, and that the changes inEand ΔW/Wwith frequency, in dry rocks, are due to a small viscous mechanism operative at low freque

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1962.tb02002.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractA series of laboratory and field experiments has proved the validity of theoretical formulae for the geophone‐to‐ground coupling characteristics. Soil properties and geo‐phone mass and size have been studied. It has been shown that soil properties in the immediate vicinity of the geophone determine the coupling, together with geophone mass and size.Statistical studies of coupling characteristics have been conducted on various soils. In some cases the dispersion of resonance frequencies and damping constants is quite large, even when the geophones have been carefully planted.As a rule, it may be said that geophone‐to‐ground coupling is not a source of trouble except ‐in high‐frequency studies. However, the filtering effect of multiple geophones may be affected by the statistical fluctuations of coupling on a given type of soil, even at usua

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1962.tb02003.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe results obtained from a series of geophones extending vertically from the surface down to a particularly strong reflector 450 m deep have provided an insight into the properties of the various types of wave generated by an explosion in the ground and have shown how these waves are converted into other types near the surface and at a reflector. The direct shear pulse generated by an explosion was observed to be quite simple and to penetrate to the deepest geophone even from large horizontal distances, but to be much more attenuated and broadened on its way through the earth than the compressional pulse. This shear pulse was found to be the cause of the ground‐roll commonly observed at the surface. A clear PS reflection, of the same magnitude as the PP reflection, was observed from the reflector 450 m deep. This shear event starts out from the reflector as a short and simple pulse, but does not persist as such on its way to the surface. It loses its sharpness well before reaching the base of the weathered layer, whereas the reflected compressional pulse is hardly affected at al

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1962.tb02004.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractFor a given refraction time‐distance curve, the range in thickness for a hidden intermediate layer is given together with the effect the layer has on the total thickness of the two layers above the recorded refracto

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1962.tb02005.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractAmong the means of comparing experimental anomalies with theoretical ones, logarithmic master curves constitute a very practical procedure. Theoretical anomalies for a large number of simple structures have been calculated once for all and drawn on logarithmic scale, in a condensed and handy way. The experimental anomalies are all represented in the same manner, and comparison with the master curves reveals one or several gravimetrically valid structures. If many master curves are available, various hypotheses can be put to the test.Logarithmic master curves have the advantage of taking into account the whole of the anomaly to be interpreted. For each structure they furnish all parameters defining it: depth, dimensions, density contrast. As master curves can be used very quickly, several hypotheses for each anomaly can be tried out in a very short time, so as to associate a group of possible structures with the anomaly. This seems to be the best way of coping with the indeterminateness of the gravimetric method.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1962.tb02006.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractParasnis' method of obtaining the gravity anomaly of circular laminae can in some cases lead to large errors. The use of the solid angle chart given by Nettleton (1942) is suggested instead.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1962.tb02007.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe theoretical radiometric anomalies caused either by a pinpoint source or by a larger one, which could be detected 75 metres above the source by a mobile detector with a very low velocity and time constant, were treated by an analog simulator which gave the curves transformed by the effect of velocity and time constant. The characteristics of these curves are discussed.An actual airborne survey above a radioactive anomaly of small surface yielded results which are analyzed and compared with the previous theoretical data. The degree of agreement between theoretical and experimental results seems satisfactory.This study shows that the deformation of curves by velocity and time constant in most actual surveys is small enough when the product of velocity and time constant is less than 75 m for a flying altitude of 75 m.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1962.tb02008.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe paper deals with the calculation of the potential distribution over various polarized bodies; the potential profiles are plotted on a double‐logarithmic net. For a quantitative evaluation the field graphs, plotted likewise in a logarithmic scale, are compared with model graphs. The method is explained by means of several examples, in which potential graphs of a single, as well as of several disturbing bodies lying close to each other, are interpreted. The practical examples have been derived from selfpotential measurements which were carried out above graphite deposits in the southern Bavarian woods.This method is generally valid for the interpretation of potential graphs of arbitrary dipoles. Therefore it can also be applied – in a slightly modified form – for the interpretation of magnetic measurements. An appropriate method of interpretation for this purpose is being pre

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1962.tb02009.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Books reviewed in this article:The Earth Today, edited by A. H. Cook&T. F. GaskellG. Porstendorfer, Tellurik: Grundlagen, Messtechnik und neue Einsatzmöglich‐keitenPhotogeology, by VictorC. Miller, assisted by CalvinF. Mil

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1962.tb02010.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY