Combining seismic reflection with multifold wide-aperture profiling: An effective strategy for high-resolution shallow imaging of active faults

Abstract

Shallow imaging of fault zones is a challenging task. We investigate if this issue can be successfully addressed by combining reflection seismics with non-standard multifold wide-aperture profiling, a strategy pertaining to crustal scale exploration so far. Near-offset reflection and multifold wide-aperture data are simultaneously recorded along two profiles in a small basin crossed by an active fault in Southern Italy. Imaging consists of multiscale seismic tomography complemented by CDP processing of near-offset reflections and of data spanning a large offset range. By combining smooth Vp and reflectivity images we pinpoint the fault location and yield a valuable picture of the basin. Performance of each exploration technique strongly varies in the two surveys depending on the local geologic conditions. Thus, the combined exploration strategy not only yields complementary images for enhanced interpretation, but also allows extending the range of applicability of shallow seismics for fault detection, reducing the risk of unsuccessful investigations.