Electrical Conductivity Anomalies in Northern France and along the Channel Coasts

1972 ◽  
Vol 235 (57) ◽  
pp. 94-95 ◽  
Author(s):  
J. C. ROSSIGNOL
Keyword(s):  
Electrical Conductivity ◽  
Northern France ◽  
Conductivity Anomalies

Shallow Magnetic Induction Measurements for Delineating Near-Surface Hot Groundwater Sources in Alaskan Geothermal Areas

1983 ◽  
Vol 105 (2) ◽  
pp. 156-161 ◽  
Author(s):  
T. E. Osterkamp ◽  
K. Kawasaki ◽  
J. P. Gosink
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Induction ◽  
Hot Springs ◽  
Measured Temperature ◽  
Conductivity Data ◽  
Induction Method ◽  
Near Surface ◽  
Saline Groundwater ◽  
Geophysical Surveys ◽  
Conductivity Anomalies

Variations in the electrical conductivity of a soil and water system with temperature and salt concentration suggest that a soil containing hot and/or saline groundwater may be expected to have a higher conductivity compared to a cooler and/or less saline system. Temperature and conductivity surveys were carried out at Pilgrim Springs, on the Seward Peninsula, and at Chena Hot Springs, near Fairbanks, to test the use of a magnetic induction method (which measures electrical conductivity) for delineating near-surface hot groundwater sources in geothermal areas surrounded by permafrost. Comparison of the temperature data and conductivity data from these surveys demonstrates that the conductivity anomalies, as measured by the magnetic induction method, can be used to define the precise location of hot groundwater sources in these geothermal areas with the higher temperatures correlating with higher values of conductivity. Magnetic induction measurements of conductivity can also be used to define the lateral extent of the thawed geothermal areas (used for calculating the stored energy) in permafrost terrain. The utility of these magnetic induction measurements of conductivity for reconnaissance geophysical surveys of geothermal areas is that a much greater density of data can be obtained in a shorter time in comparison with shallow temperature measurements. In addition, it is simpler, cheaper and easier (physically) to obtain the data. While conductivity anomalies can result from other than hot and/or saline groundwater, these conductivity data, when coupled with a few measured temperature profiles and groundwater samples, should result in reliable reconnaissance level geophysical surveys in Alaskan geothermal areas.

Electrical conductivity anomalies in the earth

1978 ◽  
Vol 3 (3) ◽  
pp. 225-253 ◽  
Author(s):  
Yoshimori Honkura
Keyword(s):  
Electrical Conductivity ◽  
The Earth ◽  
Conductivity Anomalies

scholarly journals On the sensitivity of surface NMR in the presence of electrical conductivity anomalies

2012 ◽  
Vol 189 (1) ◽  
pp. 331-342 ◽  
Author(s):  
J. A. Lehmann-Horn ◽  
M. Hertrich ◽  
S. A. Greenhalgh ◽  
A. G. Green
Keyword(s):  
Electrical Conductivity ◽  
Conductivity Anomalies

Investigation of dryland salinity using the electrical image method

Soil Research ◽  
1999 ◽  
Vol 37 (4) ◽  
pp. 623 ◽  
Author(s):  
R. I. Acworth
Keyword(s):  
Electrical Conductivity ◽  
Salt Content ◽  
Image Method ◽  
Dryland Salinity ◽  
Conductivity Variation ◽  
South Wales ◽  
Electrical Imaging ◽  
Profile Line ◽  
Conductivity Anomalies ◽  
A Site

Electrical imaging is a 2-dimensional investigation method that can be used to rapidly determine subsurface conductivity variation. In dryland salinity studies, electrical imaging is used to define the vertical extent of high electrical conductivity zones first identified using electromagnetic (EM) profiling equipment. Field techniques are described using 25 or 50 electrodes, connected to a resistance meter by a multi-core cable, to obtain images at a variety of electrode separations. The model of electrical conductivity variation obtained by an inversion of the field data is shown to agree very well with the results of detailed field investigations, including data from soil sampling, 1 : 5 extract analysis, and borehole electrical conductivity logging. Results are described from the Liverpool Plains at Yarramanbah Creek and Round Island, where a thick sequence of smectite clay overlies sands and gravels. The image clearly identifies zones of high salt content in the clay which have been sampled and logged using borehole measurements of electrical conductivity. Results are also described from a dryland salinity area in the upper part of Dicks Creek catchment on the Southern Tablelands of New South Wales. These data show the extent of clay overlying bedrock and correlate very well with the results of 1 : 5 extract analysis from shallow piezometers along the profile line. Electrical imaging is an appropriate follow-up method for the investigation of electrical conductivity anomalies first identified by EM profiling and is advisable before drilling at a site to optimise the location of piezometers.

scholarly journals Electrical conductivity anomalies in the contact zones of Archean and Proterozoic geobloks on the Ukrainian and Baltic Shields

2018 ◽  
Vol 40 (5) ◽  
pp. 208-244 ◽  
Author(s):  
I. Rokityansky ◽  
E. Yu. Sokolova ◽  
A. V. Tereshyn ◽  
A. G. Yakovlev ◽  
Working group LADOGA
Keyword(s):  
Electrical Conductivity ◽  
Contact Zones ◽  
Conductivity Anomalies

scholarly journals Error Analysis in Measured Conductivity under Low Induction Number Approximation for Electromagnetic Methods

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
George Caminha-Maciel ◽  
Irineu Figueiredo
Keyword(s):  
Electrical Conductivity ◽  
Error Analysis ◽  
Linear Relationship ◽  
Relative Error ◽  
Geophysical Prospecting ◽  
Theoretical Error ◽  
Electromagnetic Methods ◽  
Conductivity Anomalies ◽  
Linear Fit

We present an analysis of the error involved in the so-called low induction number approximation in the electromagnetic methods. In particular, we focus on the EM34 equipment settings and field configurations, widely used for geophysical prospecting of laterally electrical conductivity anomalies and shallow targets. We show the theoretical error for the conductivity in both vertical and horizontal dipole coil configurations within the low induction number regime and up to the maximum measuring limit of the equipment. A linear relationship may be adjusted until slightly beyond the point where the conductivity limit for low induction number (B=1) is reached. The equations for the linear fit of the relative error in the low induction number regime are also given.

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