Geophysical Journal | 2016 volume 38 2

Results of experimental electromagnetic studies of the Crimean region

© T.K. Burakhovich, A M. Kushnir, I.Yu. Nikolayev, Ye.M. Sheremet, B.I. Shirkov, 2016

Spatial-temporal pattern of distribution of geomagnetic variations and electric field on the Earth's surface was obtained as a result of modern experimental observations conducted in 2007-2013 along 9 profiles (48 points) by the methods of magnetotelluric sounding (MTS) and magnetovaria- tion profiling (MVP). These profiles cross various geological structures of the Crimean region. It is possible to estimate the value of electrical conductivity and vertical and horizontal geo-electric structure. The processing of these data is done using modern software system PRC_MTMV (author Iv.M. Varentsov) that provides the common noise-protected evaluation of the impedance, tipper and horizontal magneto-variation response according to synchronous MT/MV records.
  The main result of qualitative interpretation of geo-electric research is the detection of high conductivity regions in the Earth's crust and upper mantle of the Crimea, that are characterized by the variations of conductivity, depth and configuration. They characterize the various geological structures differently. The sub-vertical conductive zones often coincide with the fault structures, most of these objects are confined to the suture zones between tectonic elements such as the East European platform and the Scythian plate, the Scythian plate and the Crimean mountain, North and South Kerch zone. This fact may reflect high permeability of the suture zones for deep fluids in the process of their formation.
  Some high conductivity anomalies are well-described in the literature and are known. For example, the unique Tarhankut conductivity anomaly, located not only on the eponymous peninsula of Crimea, but also under the water area of the north-western part of the Black Sea. This anomaly was detailed and adjusted and involves a complex multi-level deep structure of the region. In addition, the structurally complex conductivity anomaly is assumed in the Sivash graben and the Kerch Peninsula.
  Although the qualitative interpretation of the experimental data of magnetotelluric sounding (MTS) and magnetovariation profiling (MVP) provides inconsistent understanding of the depth distribution of the Crimean region electrical conductivity, the combination of these methods allows constructing the model of resistivity distribution within a three-dimensional environment much more accurately and adequately to the observed experimental data.

Key words: experimental electromagnetic studies, anomalies of conductivity, the Earth's crust and upper mantle, the Crimean region.

<<back |