Geoelectric studies of the Kozloduy nuclear power plant region, Bulgaria


  • I. Logvinov Subbotin Institute of Geophysics of the National Academy of Sciences of Ukraine, Ukraine
  • G. Boyadzhiev Institute of Mathematics and Informatics of the Bulgarian Academy of Sciences, Bulgaria
  • B. Srebrov Institute of Mathematics and Informatics of the Bulgarian Academy of Sciences, Bulgaria
  • L. Rakhlin Research Centre GEOMAGNET, Ukraine
  • G. Logvinova Subbotin Institute of Geophysics of the National Academy of Sciences of Ukraine, Ukraine
  • S. Timoshin Research Centre GEOMAGNET, Ukraine



conductivity, seismicity, nuclear power plants of Bulgaria


The task of the work was geoelectrical studies using variations of the magnetotelluric (MT) field of the Kozloduy nuclear power plant (KNPP) region and the integration of its results with other geological and geophysical knowledge. This paper presents the determined interpretation parameters of the MT field. The KNPP is located on the right bank of the Danube River in close proximity to the river. This fact, together with the location of electrified railways determined the unique network of locations of observation points for MT field variations. Based on the analysis of Earthquake Catalogs of Bulgaria and international seismicity databases, a map of the seismicity of nuclear power plant areas was built. Over the past 50 years, about 750 earthquakes (mainly south of KNPP) have been recorded at a distance of 40—80 km from the KNPP. Two magnetotelluric stations GEOMAG-02 were used at measurement sites, but equipment for recording electrical channels was available only for one station (due to the lack of another set of non-polarizable electrodes). The MT field variations were observed at 21 points, which are located on the territory with sides approximately 30—35 km from east to west and 40—50 km from north to south. For all observation points on the profile, only the parameters of the vertical magnetic transfer function (VMPF) were determined, in the form of the real (Cu) and imaginary (Cv) parts of the induction vector. The steadily induction vector was defined for periods from 10—20 to 4900—10 800 s. For most points it was possible to estimate the values Cu, Cv with an error of 0.02—0.04 and AzCu, AzCv 3—5°. The analysis showed the presence of anomalous behavior of Cu, Cv in different intervals of periods at some points. In the shortest (about 20 s) and longest periods (600 to 1000 s), the Cu directions completely coincide and indicate the presence of anomalous conductivity of the quasi-longitudinal strike to the west of the study area. This behavior of the Cu vector is in good agreement with power isohypsum strike of the Cenozoic deposits. At intermediate periods of 50—200 s, the behavior of Cu is more complex. Approaching the zone of high seismicity, the direction of the Cu differs from the previous ones by almost 90°. On the Geoelectrical sections, obtained as a result of 1D inversions of MTS curves at 4 points located in the southern part of the region, anomalous layers are identified (ρ about 10 ohm · m, the depth of the center of the object is 15—20 km). It can be assumed that well-conducting objects in the Earth’s crust of the region, apparently, prevent the propagation of seismic waves from nearby earthquakes to the north towards the KNPP.


Akasofu, S.-I., & Chapman, S. (1973). Solar-terrestrial physics. Quarterly Journal of the Royal Meteorological Society, 99(422), 793—845.

Berdichevsky, M.N., & Dmitriev, V.I. (2008). Models and Methods of Magnetotellurics. Springer, 563 p.

Constable, S.C., Parker, R.L., & Constable, C.G. (1987). Occam’s inversion: a practical algorithm for the inversion of electromagnetic data. Geophysics, 52(3), 289—300.

Dobrodnyak, L., Logvinov, I., Nakalov, E., Rakhlin, L., & Timoshin, S. (2014). Application of magneto-telluric stations (Geomag-02) in geoelectric studies on the territory of Bulgaria. Seminar proceedings, 16—20 December, 2013 INRNE-BAS, Sofia, Bulgaria (Vol. 3, pp. 148—151).

Gordienko, V.V., Gordienko, I.V., Zavgorodnyaya, O.V., Kovachikova, S., Logvinov, I.M., Tarasov, V.N., & Usenko, O.V. (2005). Ukrainian Shield (Geophysics, Deep Processes). Kiev: Korvin Press, 210 p. (in Russian).

Iossifov, D.S., Zagorchev, I.S., & Bojan, I.I. (1994). Balkans. In A.V. Chekunov (Ed.), Lithosphere of Central and Eastern Europe: Young platform and Alpine fold belt (pp. 161—190). Kiev: Naukova Dumka (in Russian).

Ladanivskyy, B.T. (2003). Algorithm for processing MTZ data. Fifth geophysical readings named after V.V. Fedynsky February 27—March 01, 2003. Abstracts of reports (pp. 134—135) (in Russian).

Ladanivskyy, B., Logvinov, I., & Tarasov, V. (2019). Earth mantle conductivity beneath the Ukrainian territory. Studia Geophysica et Geodaetica, 63, 290—303.

Logvinov, I., Gordienko, I., & Tarasov, V. (2020). The results of geothermal and geoelectric studies in the regions of Rivne, Khmelnitsky and Uzhno-Ukrainsk NPPs. Geofizicheskiy Zhurnal, 42(6), 164—175. (in Russian).

Parker, R.L., & Whaler, K.A. (1981). Numerical method for establishing solution to the inverse problem of electromagnetic induction. Journal of Geophysical Research: Solid Earth, 86(B10), 9574—9584.

Schmucker, U. (1970). Anomalies of geomagnetic variations in the southwestern United States. Bulletin of the Seripps Institute of Oceanography University of California, 13, 13—32.

Scientific Report the project «The geomagnetic field under the heliospheric forcing. Determination of the internalstructure of the Earth and evaluation of the geophysical hazard produced by solar eruptive phenomena». Program IDEI, Contract 93/5.10.2011, Stage I-III. Institute of Geodynamics Romanian Academy. 2013. 28 p. Retrieved from /engl/index.html.

Srebrov, B., Ladanivskyy, B., & Logvinov, I. (2013). Application of space generated geomagnetic variations for obtaining geoelectrical characteristics at Panagyurishte geomagnetic observatory region. Comptes rendus de l’Acade’mie Bulgare des Sciences, 66(6), 857—864.

Srebrov, B., Logvinov, I., Rakhlin, L., & Kovacikova, S. (2018). Results of the magnetotelluric investigations at geophysical observatories in Bulgaria. Geophysical Journal International, 215(1), 1656—180.

Turbitt, C., Matzka, J., Rasson, J., St-Louis, B., & Stewart, D. (2012). An instrument performance and data quality standard for INTERMAGNET one-second data exchange. In XVth IAGA Workshop on Geomagnetic Observatory Instruments and Data Processing, Cadiz, Spain, 4—14 June 2012 (pp. 186—188).

Varentsov, I.M. (2007). Joint robust inversion of MT and MV data. In Electromagnetic sounding of the Earth’s interior (Methods in geochemistry and geophysics) (pp. 189—222). Elsevier.

Zagorchev, I. (2009). Geomorfological formation of Bulgaria. Principles and state of the art. Comptes rendus de l’Acade’mie bulgare des Sciences, 62(8), 981—992.




How to Cite

Logvinov, I. ., Boyadzhiev, G. ., Srebrov, B. ., Rakhlin, L. ., Logvinova, G. ., & Timoshin, S. (2022). Geoelectric studies of the Kozloduy nuclear power plant region, Bulgaria. Geofizičeskij žurnal, 43(6), 3–22.