摘要:

AbstractUsing plane wave theory and assuming a given input wavelet the shape of the reflected (or transmitted) wavelet from a layered boundary is derived. Several types of boundaries are considered, among them the weathered layer and a wedge shaped intermediate layer. Different angles of incidence and all internal multiples are taken into account. The examples shown in the figures can be used for a direct comparison between theoretical and observed shapes of reflected (or transmitted) wavelets from special boundaries.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1969.tb02069.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractSeismic refraction measurements were made in two areas of the Baltic Sea in June 1967. The refraction data were obtained in the course of the transmission measurements program of Operation MILOC BALTIC 67.Three profile pairs were obtained, two in the area south of Öland Island, Sweden, the third to the east, north of the peninsula of Hel, Poland. The water depths vary from 60 to 90 meters between the areas.The receiving positions for the two profiles south of Oland Island are only 46 km apart but the structures differ markedly. The northern section, only 500 m thick, shows a rather thin sedimentary cover above 350 m of 3.7 km/sec material that in turn overlies 5.6 ‐ 5.9 km/sec velocity material. The southern section, almost 2 km thick, has an equivalent amount of low velocity material, and a layer about 1 km thick having velocity 4.8 km/sec that overlies 6.0 km/sec velocity material. The eastern profile shows high velocity material, 5.6 km/sec, at 2.5 km depth.Correlation of the layers determined by seismic refraction with nearby geology suggests that the structural change south of Öland Island may represent the boundary of the Sarmatian Shield in this reg

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1969.tb02070.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractConsiderable water leakages from reservoirs make it difficult to attain the planned storage capacity. In some cases water leakages give rise to suffusion followed by catastrophes. Until recently methods for locating water leakages were extremely imperfect. Geophysical methods offer good prospects in this direction. For solving these problems, it is effective to use streaming potential measurements, water flow rate observations and thermometry.Laboratory experiments were carried out in connection with the fact that water leakages from reservoirs are characterized by negative anomalies of natural currents; the more filtration discharge, the higher these anomalies are. As a result, the relationship governing the intensity of streaming potential and sand granulometric composition, electrolyte concentrations and other factors were revealed. To determine the velocity of water flowing to leakage sites, a special device, based on the relationship between the temperature of a heated body and its resistance, is applied. This device simultaneously makes it possible to measure the water medium temperature.Observations at reservoir sites were effected by moving along the reservoir non‐polarizable potential electrodes and water velocity devices. Recordings were carried out automatically by the recording device of the logging apparatus. Under the conditions of ice cover on water surfaces, measurements were made through separate points by digging holes in the ice cover.Practical field observations were carried out at reservoir sites located in regions where fissured massive rocks as well as loose sediments predominate. In the first case field experiments were carried out in alpine reservoirs, in Armenia. The major water leakages were found to be concentrated on the right bank of the reservoir. In this connection it was not only possible to locate water leakage sites, but also to evaluate their relative intensity. These data were used for planning antifiltration measures. In the second case water leakages from a reservoir located in Uzbekistan in the submontane part of the Pamirs were studied. Streaming potential anomalies and high benthonic flow rates made it possible to discover high filtrations in the base and walls of the dam.Further perfection of these methods should not only permit the determination of water leakage sites and their relative intensity, but also filtration discharges in absolute unit

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1969.tb02071.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractElectrical resistivity anomalies of a symmetrical four‐electrode co‐linear system across a single vertical discontinuity are treated in relation to: a) the ratio of potential electrode separation to the current electrode separation that are employed in the system and b) the angle which the electrode alignment makes with the discontinuity. Several conclusions are extracted from this treatment and methods for obtaining an optimum sensitivity of the system, with respect to these parameters, are shown. Disadvantages of special arrangements, such as the Wenner configuration, are indicated. Methods are outlined to utilise variations in the apparent resistivity plot for determining the angle between the electrode alignment and the discontinuity, quantitatively or qualitatively. These variations include certain deviations from the standard curves obtained in longitudinal traverses made at right angles to the discontinuity. Also, a comparison is made between longitudinal and cross traverses, in relation to the discontinu

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1969.tb02072.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe transient fields from a finite horizontal loop excited by a half sine wave current pulse have been computed numerically for a particular source receiver configuration at a height of 100 meters above a layered ground. The amplitude of the vertical component of the magnetic field has been chosen for the interpretation. Curves of apparent conductivity vs. time, plotted during the off‐time of the signal, show that layering is easily resolved, that resonance effects are present and that polarization effects are detectable for certain types of polarizatio

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1969.tb02073.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1969.tb02074.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY