Fig. 12

a–c Attribute maps of root mean square amplitudes above and below BMz. The maps show the results of amplitude extractions within certain observation windows with high amplitudes in red and yellow and low amplitudes in dark blue and purple. The relevant amplitude extraction window is characterised by its “offset” from BMz (positive in downward direction) and its “length” (vertical extent), both specified in two-way travel time. Note that the schematic sketches of the observation window dimensions at the top left of the figures are not to scale. a 20 ms thick window directly above BMz. The main structural features (SFZ, RFZ, Unterlören Graben, MFZ) are clearly highlighted by significant contrasts in amplitude. Note the NNW–SSE striking change of amplitudes east of the Unterlören Graben between the northern termination of the RFZ and the MFZ (marked by two red arrows). b 100 ms thick window at 10 ms underneath BMz. Note the SW–NE striking, high-amplitude anomaly (A) directly northeast of SG GT-1. This anomaly marks the PC reflections on the assumed crystalline horst discordantly underlying BMz (see also Figs. 8b–d and 11). c 1000 ms thick window at 100 ms underneath BMz encompassing three areas with probable PC reflections (B, C and a fourth one marked by the red arrow). d Interpretative structural map of the basement at the level of BMz (i.e. top basement) highlighting the areas of probable and possible PC occurrences. These areas are compiled from b, c and the interpretation of vertical reflection seismic sections. Note that the distinction between the areas designated as “PC possible” and “undifferentiated basement” is rather speculative