|
Vladimir Semenov, Institute of Geophysics PAS (Poland)
Waldemar Jozwiak, Institute of Geophysics PAS (Poland)
Antal Adam, Geodetic and Geophysical Research Institute HAS (Hungary)
Boris Ladanyvskyy, Carpathian Branch of the Institute of Geophysics NAS (Ukraine)
Igor Logvinov, Institute of Geophysics NAS (Ukraine)
Josef Pek, Geophysical Institute ASCz (Czech Republic)
Pavel Pushkarev, Moscow State University (Russian Federation)
Jan Vozar, Geophysical Institute SAS (Slovakia)
|
|
During 2001 to 2003, we accomplished the experimental phase of the project CEMES (Central Europe Mantle geoElectrical Structure) by collecting long period magnetotelluric data at positions of eleven permanent geomagnetic observatories situated within few hundreds of kilometers along the south-west margin of the East European Craton. Five teams were engaged in estimating independently the magnetotelluric responses by using three different data processing procedures. The individual estimates were averaged, rotated into a direction conforming best the E-mode approximation, and further combined with scalar ultra-long magnetovariation responses from the geomagnetic observatory records to expand the period range of the data up to several years.
We have applied the spherical forward modeling to assess the influence of the surface non-uniform conductance, specially collected over the region of the CEMES experiment, on the results of the deep sounding. Then, the conductivity and conductance distributions at the depths of the upper mantle have been derived individually beneath each observatory, by employing four different 1 D inversion techniques independently by five interpretation teams. By averaging the individual electrical sections, we have designed the final model of the geoelectrical structure of the upper mantle beneath the CEMES region. We present the model in the form of slices of the total conductance at various depths in the mantle. The results indicate systematic trends in the deep electrical structure of the two principal European tectonic plates and give evidence that, similarly as the seismic properties, also the electrical structure of the upper mantle differs between the East European Craton and the Phanerozoic plate of west Europe, with a separating transition zone that generally coincides with the Trans-European Suture Zone.
* Experimental Team of CEMES is listed in Eos 1 52, 30 December, 2003.
|
