| Popis: |
Summary A small scaled 3-D P-wave survey (0.018 km2) in an overdeepened valley of the Rhine Glacier (Tannwald Basin) revealed glacio-tectonic structures at depths of 20–50 m, interpreted as cuspate-lobate folding. Previous 2-D lines, processed using prestack depth migration (PSDM), only displayed a region with poor imaging quality. A careful reprocessing of the 2-D data using common reflection surface (CRS) and prestack time migration (PSTM) now gives an image matching the high-resolution of the 3-D data. The glacio-tectonic structures exhibit very low velocities that were not accounted for in the PSDM processing and led to a distortion of deeper layers. Based on the PSDM migrated 2-D data, we speculated about a deep-reaching tectonic fault zone, which is not probable anymore in the light of the reprocessed data. |
