Section 3: Integrative Approaches
High-resolution reflection seismic profiles were acquired at two study sites in the Upper Rhine Graben, Germany, to image fault zones in the near-surface domain. The profiles fill the gap left by large-scale 3D seismic imaging focused on targets several kilometers deep. The survey design comprises a very dense sampling of reflection points with frequencies as high as 360 Hz emitted by a small hydraulic vibrator. Dip-moveout processing with poststack migration is required to image the fault systems properly. At the first study site, a broad normal fault zone with a width of about 300 m was imaged. It shows two major faults accompanied by numerous smaller parallel and subparallel faults. At the second study site, the survey reveals a horst structure with two bounding normal faults that branch into several smaller ones with depth. Thicker sedimentary units in the hanging walls of the faults suggest synsedimentary fault growth. Significantly, the high-resolution, 2D near-surface seismic measurements provide deeper insight into the architecture and kinematics of the fault systems than is possible from 3D measurements that are focused on deeper targets.