ZusammenfassungEs werden die drei Methoden: erdmagnetische Tiefensondierung, Tellurik oder E-Feld-Messung und Magnetotellurik erl~iutert (Abb. 1, 2, 4 und 5).L~ings AbstractThe three methods: geomagnetic deepsounding, tellurics or E-field-measurements, and magnetotelluries are explained (Abb. 1, 2, 4 and 5).The electric field E produced by electromagnetic induction in the earth was observed following two profiles crossing the Molasse basin N of the Alps, Southern-Germany (Abb. 8). Transportable electrographs were used. The horizontal induced geoelectric field is nearly elliptically polarized. The direction of the major axes of these ellipses which approximate the veetordiagrams, is called the preference direction under special conditions. The preference directions of E are systematically orientated in the Molasse basin (Abb. 8). The intensity of E is smaller in the Molasse than it is in the area of crystalline rocks. The thickness of the sedimentary layer of good conductivity can be estimated by means of the relation q = ]/[-(Exo2 § Eye 2) wandering station / (Exo 2 @ Eyo~ ) basSs station]. Ero and Ey o are tlae maximal components between the beginning and the end of an event (Abb. 6).