HR: 1340h
AN: GP33B-1250    [Abstracts]
TI: Invariant-based imaging and interpretation of magnetotelluric measurements over an area and along a profile in SW-Transdanubia, Hungary
AU: Novak, A
EM: novak@ggki.hu
AF: Geodetic and Geophysical Research Institute, Csatkai u. 6-8., Sopron, H-9400, Hungary
AU: * Szarka, L
EM: szarka@ggki.hu
AF: Geodetic and Geophysical Research Institute, Csatkai u. 6-8., Sopron, H-9400, Hungary
AU: Pracser, E
EM: pracser@elgi.hu
AF: ELGI, Kolumbusz u. 17-23., Budapest, H-1145, Hungary
AU: Adam, A
EM: adam@ggki.hu
AF: Geodetic and Geophysical Research Institute, Csatkai u. 6-8., Sopron, H-9400, Hungary
AB: We applied various imaging and interpretation approaches to a magnetotelluric data set in SW-Transdanubia, Hungary: a) data from about 300 MT soundings, carried out over an area of about 40 km x 25 km, and b) data from about 100 MT soundings, measured along the CELEBRATION 007 profile with a step distance of appr. 2 km. Different authors had recommended different solutions for the invariant presentation of the magnetotelluric results: the so-called SM-, WAL-, phase tensor invariants, and all decomposition techniques also belong to this category. In this paper we give a systematic summary about the results obtained with all these parameters in a wide period range. In all approaches it should be kept in mind, that the magnetotelluric impedance tensor contains seven (not more and not less) real data of about the resitivity distribution of the subsurface. While we have got a mixed experience with some fashionable invariant parameters calculated from field data, some phase- and the real tensor invariants have proven to be useful. They indicated deep structures at unambigously shorter periods than the common resistivity or imaginary tensor-based data. It is also interesting that the phase tensor suggests less thicker deep structures than expected from geology. SW-Transdanubia is crossed by two main tectonic lines: the Mid-Hungarian- and the Balaton lines. The Mid-Hungarian line, although it separates the two basic units of the Pannonian Basin (Alcapa and the Tisia), seems to have weeker and more intermittent magnetotelluric features than the very robust Balaton line.
DE: 0699 General or miscellaneous
DE: 0905 Continental structures (8109, 8110)
DE: 0910 Data processing
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting