Recognition of intra-basaltic horizons from challenging marine seismic data in the Faroe Islands

High‐resolution 2D marine reflection seismic data were acquired in a narrow sound in shallow water with high acoustic‐impedance contrasts. This yielded a volume of raw data with very strong, short‐period multiples and weak signal below the seabed, implying extra demands for the processing. In order to avoid the loss of useful signal when attempting to enhance the S/N, a powerful f‐k filter was used early in the processing, followed up by post‐stack deconvolution and migration. In spite of extraordinary challenges and drawbacks in the processing the final result is promising, with stacked sections that depict intra‐basaltic horizons. Some of those horizons can be identified from onshore extrapolation of their recognized positions and attitudes. After preliminary interpretation of the tight grid of seismic lines, a 3D horizon could be derived for better visualization, and this work can be used to test a recently hypothesized strike‐slip fault in the study area. Consequently, as many research projects are carried out aiming at sub‐basalt imaging ‐ mostly with the application of low‐frequency sources and the utilization of the bubble pulse for deeper penetration ‐ this work exhibits the use of a high‐frequency seismic source for intra‐basalt imaging in the uppermost few hundred meters with quite interesting results.