Tunnel valleys as geohazards: New insights from high-resolution 3D seismic data

High-resolution 3D seismic data are used to analyse the infill of buried tunnel valleys in the North Sea. The level of detail provided by the high-resolution three-dimensional seismic data (6.25 m bin size, ~4 m vertical resolution) represents a step-change in our ability to investigate the internal architecture of tunnel valleys and their role as geohazards. We discover that over 40 % of the tunnel valleys examined contain buried glacial landforms including eskers, crevasse squeeze ridges, glacitectonic structures, and kettle holes. Due to the association of these features with shallow gas, the tunnel valleys which contain them have implications as geohazards for shallow drilling and infrastructure installation efforts.