Seismic imaging of staircase layers below the Mediterranean Undercurrent

Seismic images of staircase layers at the bottom of the Mediterranean Undercurrent with a lateral coherence up to 50 km and a horizontal resolution of ∼ 10 m are presented. The images show clearly the interaction between these staircase layers and other flow structures such as meddies, seamounts and internal waves. The staircase layers were imaged during two different surveys that used different sound sources. Comparison between seismic images and historical oceanographic observations illustrates the importance of using a seismic source adapted to the vertical scale of the oceanographic target to be imaged. Wavelengths larger than the size of the staircase structure distort the image in the vertical. For optimal imaging, deconvolution of the data is required.