Electromagnetic measurements in the vicinity of the KTB drill site. Part II. Magnetotelluric results

The Present State of Art of Long Period Magnetotellurics in the Western Part of the Bohemian Massif

“…Similarly as the regional strike estimate, the telluric deviations are also sufficiently stable within the period range studied, with relatively large mean values, /31 ~ -35.1° and /j2 ~ 29.6°, which indicates rather large distortions of the telluric field at the locality investigated. A more detailed analysis of the MT data from the particular locality OSTR in Cerv et al (1993) showed further that a stable apparent local strike can be derived from the data, close to the azimuths of the real reference station induction arrows mentioned earlier. Different estimates of the apparent local strike are concentrated within the range of 40 to 50 degrees, and, although we cannot attribute them to any particular tectonic feature, they conform well with the roughly SE-NW and SW-NE strikes of the regional geology.…”

“…1. The data were already analyzed in (Cerv et al, 1993) in detail. The main conclusions based on the behaviour of both the single station and reference station geomagnetic transfer functions (with the observatory Budkov in South Bohemia as the common reference station, Fig.…”

“…In (Cerv et al, 1993) an attempt was made to estimate the absolute static shifts at the site OSTR by repeating Eisel's approach of fitting the long period branches of the local MT curves to Schmucker's continental GDS curve (Eisel, 1990). As neither Eisel's nor our curves contain reliable data in the period range of the harmonics of the daily variation of the geomagnetic field, Eisel used the nearby long-period station Hanfmiihl, Germany, as a connecting link between his local MT data and the continental GDS curve.…”

“…(i) Already the decomposition attempt at the site OSTR, presented in (Cerv et al, 1993), was carried out by a rather simplified approach of Eisel (1990)-the long-period branches of the 'deskewed' curves from OSTR were fitted to the univariate 'deshifted', with respect to the continental GDS curve, impedances from the long-period station Hanfmiihl, Germany.…”