Use of bathymetry derived from Landsat Thematic Mapper to plan seismic surveys in the Red Sea

Synopsis

Landsat Thematic Mapper (TM) have been used in the Red Sea, offshore Ethiopia, to help in the planning of a seismic survey. The area has unreliable bathymetric charts and highly variable water depth.

The Landsat TM data were geocoded to the local datum and map projection to an accuracy of about 100m. Depth sounding data were digitised from the bathymetric charts and used to calibrate the Landsat data.

TM band 1 was found to give the best results, giving good water penetration and being less noisy than band 2. The calibration with depth data suggested that maximum penetration was about 20m. This is about the limit for safe operation of the seismic vessel.

These results were used to lay out the planned seismic lines in around the shoals and islands, saving much time in the design stage of the survey and removing the need for an expensive bathymetric survey.

This technique has also been used successfully with SPOT data in the Gulf of Suez.