Abstract
The profile 2S was recorded in 1984 as part of the DEKORP project, the German deep seismic reflection program. The focus of the DEKORP project was on deep crustal and lithospheric structures and therefore originally not on structures at shallower depths. From today's perspective, however, this depth range is of great interest for a wide range of possible technical applications (including medium-depth and deep geothermal projects). The original data is published by Stiller et al. (2020). The northernmost 50 km of the 250 km long profile 2S were reprocessed on behalf of the Hessian Agency of Nature Conservation, Environment and Geology (HLNUG). The focus of the reprocessing was on improving the resolution / mapping of geological structures down to a depth of 6 km (approx. 3 s TWT) to describe the prolongation of faults and geological structures in more detail than in previous studies.
In order to achieve these goals and in view of the fact that today's processing and evaluation methods have been improved considerably compared to the 1990‘s, a state-of-the-art reprocessing was implemented. In comparison with the original processing (Stiller et al. (2020)), more sophisticated processing steps like CRS (Common Reflection Surface) instead of CDP (Common Depth Point) stacking, turning-ray tomography and prestack time and depth migration were carried out.
The reprocessing results of the DEKORP 2S survey comprise all datasets newly achieved in addition to the datasets from the original processing (Stiller et al. (2020)), i.e. (1) the migrated CRS image gathers as unstacked data, and (2) the pure CRS stack, the poststack-time as well as prestack-time and prestack-depth migrated sections as stacked data. Moreover, (3) all velocity models used for the different versions including (4) the separate first-break tomography inversion, are contained.
All reprocessed data come in SEGY trace format, the final sections additionally in PDF graphic format. A reprocessing report is included as well as again all meta information for each domain (source, receiver, CDP) like coordinates, elevations, locations and static corrections combined in ASCII-tables for geometry assignment purposes.
The DEKORP 2 survey, consisting of the three segments 86-2Q, 86-2N and 84-2S, starts in the sub-Variscan foredeep of the Münsterland Basin and ends in the Moldanubian region at the Danube. The central part crosses the Rhenish Massif (Rhenohercynian), the Spessart Mountains of the Mid-German Crystalline High (Saxothuringian) and the meteorite impact location of the "Nördlinger Ries". DEKORP '84-2S, was the first DEKORP line and the only one which mainly used explosives as the seismic source. The 250 km long, SE-NW striking profile extends from the Rhenohercynian Taunus Mountains to the Danube thereby crossing the Spessart Mountains, the Hessian Trough and the "Nördlinger Ries". The profile DEKORP 2S is the southern continuation of DEKORP 2N, which intersects at profile km 246.08. The reprocessed datasets contain a sub-section of the entire 2S profile with a total length of 50 km of full CDP fold, covering the profile’s northern part through the state of Hesse.
The DEKORP '84-2S profile is of particular interest to investigate the seismic resolution of the Rhenohercynian Taunus Mountains including the Taunus ridge, as well as the Tertiary Hessian Trough, the Permian Wetterau nappe and a small part of the crystalline Spessart Mountains.
The seismic sections of 2S show clearly visible, predominantly SE-dipping reflectors indicating flat-and-ramp tectonics and a differentiation into a highly reflective lower crust and a less reflective upper crust. Due to the use of explosive shots with relatively large spacing as the seismic source, less new information could be achieved for the uppermost crust compared to the original processing and to other DEKORP (vibroseis) surveys. A clear Moho reflection is visible throughout the whole profile section at a depth of ca. 26 to 28 km.
