Use of continuous seismic profiling and side scan sonar for identification and characterization of sand banks: Case study on the inner continental shelf in the North of the Santa Catarina Island

Abstract

This work present results of an identifying and characterizing sand bank, located in the northern region of Santa Catarina Island to be used as borrow area for beach restoration projects. In this way, data from 36.2km of continuous seismic profiling were acquired using a multi-source sub bottom profilers (SBP). The applied SBP was a Boomer seismic source (frequency between 0.5 kHz and 1.5 kHz) and a high resolution Chirp (frequency between 0.5kHz and 12kHz); and 56.1 km of Side Scan Sonar data, using an interferometric sonar (multiphase bathymetry and sonography with a frequency of 540 kHz). The methodology included the processing of the data and analysis in the post-processed data. The steps of importing survey lines, data previews, bottom track and User Gain Control and filters (bandpass, swell) were performed. Finally, the identification, delimitation, analysis and quantification using the acoustic reflectors were carried out. As results, four different sites with different acoustic responses could be observed in the sonography data, which indicates the arrangement of sediments with different grain size at the studied site. In some seismic profiles was observed the occurrence of an acoustic reflector indicating the rocky basement. This profiles showed a layer of sediment about 13m thick. The volume of sediment estimated through the order of magnitude was 10.000.000 m3 for the area.