Seismic Near-Vertical Reflection Studies of the Earth's Crust in the Federal Republic of Germany

The first observations of near-vertical reflections from horizons within the crystalline basement were made by Junger (1951), Dohr (1957) and Dix (1965). Dohr's observations, obtained by standard techniques of seismic reflection methods for prospecting, were sporadic at first and gave a rather diffuse picture of the reflectivity of the continental Earth's crust in Germany. In the 1960s the sporadic measurements developed into a more general application of long-running magnetic tapes, e.g. recording (analogue) up to 12 secs two-way travel time during regular surveys of prospecting crews. In spite of many pessimistic predictions regarding the possibility of receiving any signals at all from the 'homogeneous' basement, the results showed certain clusters of true reflections at various depths of the Earth's crust (Dohr and Fuchs 1967). Especially strong arrivals were obtained at various sites from the Mohorovićić boundary (= Moho) at 10 secs two-way travel time, equivalent to a depth of about 30 km. From the rather short reflecting segments of the first surveys and from the increase of reflectivity towards the base of the crust just on top of the Moho, the concept of reflecting 'lamellas' as the transition from crust to mantle was born (Meissner 1966).