International Journal of Geophysics
Volume 2017 (2017), Article ID 3029357, 3 pages
https://doi.org/10.1155/2017/3029357

Corrigendum

Corrigendum to “Characterization of Geotomographic Studies with the EMRE System”

Arto Korpisalo

Geological Survey of Finland, P.O. Box 96, 02151 Espoo, Finland

Correspondence should be addressed to Arto Korpisalo; arto.korpisalo@gtk.fi

Received 3 May 2017; Accepted 24 May 2017; Published 30 July 2017

Copyright © 2017 Arto Korpisalo. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

In the article titled “Characterization of Geotomographic Studies with the EMRE System” [1], there were errors in the “Theory” section.

Paragraph three should be corrected as follows:

“The field depends on the distance from the source. Certain characteristics of an electromagnetic field dominate at one particular distance from the antenna, while a completely different behaviour can dominate at another location. The wave number multiplied by the distance defines the behavior [10, 11, 13]. When or at a distance much shorter than the wavelength, the electric field resembles the static dipole field, being proportional to (static term), and anything in this region that couples with the antenna will disturb the antenna severely (reactive near field). The EMRE system operates in the near-field domain due to the wavelengths of hundreds of meters when the low frequency of 312.5 kHz and short distances ( m) are used with resistivities ~10000 Ωm. When = 1, the field is proportional to (induction term), and the static term (~) becomes negligible. The region is known as a radiating near-field or Fresnel zone. With the frequency of 2500 kHz and with resistivities 10000–1000 Ωm, the EMRE system operates in the Fresnel zone at distances of ~40–80 m. When or at a distance much greater than the wavelength, the electric field is inversely dependent on the distance (radiation term). The angular field distribution is independent of the distance from the antenna (far-field or Fraunhofer zone). When the frequencies  kHz and distances  m are used with resistivities <10000 m, the EMRE system operates in the far field. The inhomogeneous generalized time-domain wave equations for the time harmonic electric field and magnetic field ( dependence) can be written as [16–18]”

Equation should be corrected as follows:

Equation for should be corrected as follows:

“Figures 2(a) and 2(b) present the cut-off frequencies () for different materials ( = 100, 1000, 10000 m and = 10, 20)” should be corrected to “Figures 2(a) and 2(b) present the cut-off frequencies for different materials ( = 100, 1000, and 10000 m and = 10, 20)”

(a)

(b)

Figure 2: (a) The attenuation () and phase () constants in a dissipative medium with = 10 and = 100, 1000, and 10000 m. (b) The phase and attenuation constants in a dissipative medium with . is the attenuation (red lines) as Nepers/m and is the phase constant (blue lines) as rad/m. The m-curve is valid when the attenuation constant equals the phase constant or (black curves).

“Increasing the relative permittivity of the medium, the cut-off frequencies decrease ( = 20) and the quasi-static conditions are valid almost up to ~60 kHz” should be corrected to “Increasing the relative permittivity of the medium, the cut-off frequencies decrease () and the quasi-static conditions are valid almost up to ~600 kHz”

Figure 2(b) is corrected hereinafter.

In addition, in the “Rim Instrument” section, the legend of Figure 4 is corrected hereinafter.

(a)

(b)

Figure 4: The electrical properties of a sulphide sample (a) and a granite sample (b) from Vogt [7].

References

A. Korpisalo, “Characterization of geotomographic studies with the EMRE system,” International Journal of Geophysics, vol. 2014, Article ID 401654, 18 pages, 2014.