Seismic diffraction imaging illuminates faults in the eastern Molasse Basin along the TRANSALP section

Seismic diffraction imaging along the north-south oriented TRANSALP seismic line across the Eastern Alps reveals hitherto unresolved seismic stratigraphy in the eastern (German) Molasse Basin as well as details of faults along the front of the Alpine orogenic wedge. The method derives its theoretical foundation from the field of optics and utilizes the diffracted seismic wavefield, which is orders of magnitude weaker than seismic reflections, but provides superior illumination of the traversed medium. Contrary to the common notion that diffraction imaging is only feasible in modern, more regular acquisition geometries such as in marine seismic data, our results show that it can also be applied successfully to less favorable datasets along TRANSALP. South of the Molasse Basin, diffractivity allows us to better distinguish the S-dipping foliation and bounding thrusts of the folded Subalpine Molasse, the Helvetic and Penninic Nappes and the Northern Calcareous Alps.