Datensatz

Zusammenfassung

The Dead Sea Transform (DST) is a major active continental shear zone at the boundary between the African and Arabian plates. The DESERT project was conducted as the first crustal-scale geoscientific investigation of the DST fault system. Here we focus on the seismic imaging of shallow structures in the close vicinity of the Arava fault (AF), the dominant fault of the DST in the study area. The seismic data used in this study represent a sub-set selected from a 100 km long vibroseis reflection line across the DST. Whereas the entire data set provided images of the whole-crustal reflectivity, the selected data were processed with special focus on the detailed, preferentially steep-dipping structures of the upper 5 km in the region around the Arava and Zofar faults. Firstly, the data were analysed with a semblance-based algorithm to detect and extract the events with strongest coherency. Then, pre-stack depth migration was carried out using isochrone calculations for a 2-D tomography-based velocity model. In the final step, the migrated reflection events were analysed and selected by consideration of several attributes from the semblance analysis and imaging procedure. The results establish a link between the crustal-scale reflection image and the near-surface studies including seismic velocity tomography and inversion of densely measured magnetotelluric (MT) data. Increased sub-horizontal reflectivity correlates with features of the MT-based conductivity model. Steep-dipping structures are imaged in the vicinity of the AF and follow the horst-like anomalies of the velocity tomogram.