P- and S-wave Seismic Imaging of Overdeepened Alpine Valleys

Overdeepened valleys and basin can be found in glaciated regions worldwide. Due to their geological, ecological, and societal relevance they constitute a relevant geoscientific target. In preparation for an ICDP project (Drilling Overdeepened Alpine Valleys, DOVE), we carried out several reflection seismic surveys using high-resolution P-wave, horizontally pola¬ri¬zed SH-wave, and multi-component (SV- and SH-wave sources, 3-component re¬ceiver) techniques at a test site in the Tannwald basin north of Lake Constance. The first results of the P- and SH-wave reflection profiles are presented here. The seismic sections image well the internal valley structure of the Tannwald Basin; different facies are also distinguishable in the glacial sediments. The combined inter¬pretation of P-wave and SH-wave reflection seismics reveal more details than just one technique on its own by providing complementary information. P-wave seismics show a more coherent image with a higher penetration depth, while SH-wave seismics partly resolve more details due to their higher resolution. The combination promises to be an enhanced tool to investigate sedimentary successions in advance of scientific drilling.