Day 17: Pictures of the underworld

By Olivia Belshaw

After spending a significant amount of time yesterday learning about the process of swathing and Bathymetry with Dr Robin Beaman, I was lucky enough to be allowed to use the multibeam processing software “HIPS and SIPS” to develop a 3D image of a previously unmapped area of the sea floor. I selected a part of the unofficially named “Lexington Seamount” and was assisted by Robin to develop the stunning image as seen below, covering an approximately 10 x 10km area of the massive seamount. The amount of sound data collected to generate these images, along with the complex level of programming involved to take into consideration factors such as water velocity, ship attitude etc. (see Day 16) is truly astounding.

The image below is an overall map of the “Lexington Seamount”. The image has been artificially coloured by depth to help scientists get a more accurate picture of the landscape. The dark sections of blue indicate the deepest part of the sea floor, whilst the red/yellow sections indicate the top of the seamount, and the areas closest to the ocean surface (even though they are still approximately 2km below the surface). The small square on the top image is the 10km x 10km section I used to create a detailed map. The top picture shows the seamount from a bird’s eye view, whilst the bottom picture shows a profile of the seamount, revealing the shape from a side on view.

The next image is a sound map of the 10km x 10km section of the Lexington Seamount. Each dot represents a sound beam that was projected down from the ship (using SONAR) and then returned. In the 10km x 10km section, thousands of sound ‘pings’ or dots have been collected to create an image of the sea floor.

Before a final image can be obtained, any points of interference or “noise” are removed, and then the image is rendered. A final image of the 10 x 10km area of the Lexington Seamount can be observed below.