The Sub-Bottom Structure of the Gulf of La Spezia
Abstract
The sub-bottom structure of the Gulf of La Spezia, Italy, has been investigated by continuous seismic profiling and sediment coring. The seismic profiles were used to develop contour plots of sub-bottom layers, which were identified from the core measurements. The seismic profiles indicated a buried barrier bar extending across the Gulf, delineated by a rise in the terminal layer from more than 15 metres below the sea floor to less than 3 metres. Acoustically-opaque, dome-shaped features ('light domes') flank the barrier-bar. An acoustically-transparent layer ('shadow layer') hugs the terminal layer at the upper section of the barrier bar. Two intermediate-depth transparent layers ('main intermediate', and 'deep intermediate' layers) are found landward of the barrier bar. The shallower of these ('main intermediate layer') terminates abruptly against either the barrier bar itself, or against the light domes fringing the bar's landwar flank. A shallow-depth transparent layer ('shallow layer') is found distributed throughout the Gulf, apparently independent of the bar's influence. Acoustically-scattering patches ('dark patches') are found both landwards and seawards of the barrier bar, exhibiting a definite tendency to zone along depressions in the terminal layer.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1968
- Accession Number
- AD0845867
Entities
People
- H. Edgerton
- L. R. Breslau
Organizations
- SACLANT ASW Research Centre