Sub-basalt imaging is challenging for a number of reasons. There is the large absorption of energy which particularly affects the high-frequency seismic signals. In addition, the large impedance contrasts associated with top and base and internal layering of the basalts, are generators of severe multiples and finally inhomogeneities within the basalts, and the sediment-basalt interface, further scatter the energy. In recent years the most common approach has been to focus on low frequencies because frequencies above approximately 40 Hz will be lost for sub-basalt signals. With standard marine acquisition this can be achieved by towing sources and streamers deep. However, this also results in losing the higher frequencies and consequently resolution in the data. Broadband seismic acquisition avoids this trade-off. In this paper we compare 2D data acquired using broadband technology to conventional deep-tow data previously acquired in the same locations over basalt in the Faroe Shetland Basin. We will demonstrate that both the signal and de-noise benefit from broadband acquisition. With a broadband signal the character of the sub-basalt signal and the noise / multiples is clearly different, potentially enabling new ways of dealing with noise and multiples.


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