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Sub-Surface Imaging at the Rockall Basin, Using Travel Time Tomography and Full Waveform Inversion
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 81st EAGE Conference and Exhibition 2019 Workshop Programme, Jun 2019, Volume 2019, p.1 - 5
Abstract
The geological structure beneath the Rockall basin and the nature of the crust are largely undefined because of the sill intrusion, lack of the seismic data coverage and deep well data penetration. The basaltic rocks prevent the seismic waves from travelling underneath them and make it hard to image below these high velocity layers. Here, we perform travel time tomography on long streamer data sets along a 80 km long profile to get a smooth P-wave velocity model using the first arrival travel time. The 2D seismic lines were acquired in 2013–14 using 10 km long streamers. We pick first arrival travel time from the shot gather after cleaning the data set. The velocity model obtained here, indicate the velocity from 1.6–4 km/s for the sediments and we also observe very high velocity ~ 6–7 km/s just 3 km below the sea-floor. This high velocity structure could be the lower crust pinching out at the Rockall high. This velocity model is used as a starting model for full waveform inversion (FWI) to get a higher resolution velocity structure.