Seismic refraction surveys have been carried out to assist with the characterisation of shallow geological structure for the planned cable landfall at Weybourne, on behalf of Scira. The primary objective of the project is to determine depths to the various geological layers of similar sediment firmness and bedrock competency beneath four profile lines. The lines were chosen by the Client to broadly investigate the geology and extend from inland areas across the storm beach and out into the sea a distance of about 300m. The survey team included five personnel, a 48-channel seismic system with land geophones for the beach and a seabed hydrophone streamer for the marine work. One boat was required for marine shots during the land aspect of the survey and two boats were required for the marine survey itself. The work was carried out over two planned phases plus a subsequent revisit to complete the marine work under more favourable weather conditions. Results include sections of modelled geological structure including poorly consolidated material, glacial tills and anticipated Chalk bedrock. Measured seismic velocities of the modelled Chalk layer suggest a weathered condition and hence a transitional rockhead is anticipated. The depth of investigation achieved by the survey is greater than 30m below OD. Modelled bedrock appears gently undulating and generally dips seaward. Much of the overburden is believed to comprise the Lowestoft Till apart from shallow weaker materials observed on land.
Geophysical Survey Report