Deep-towed side-scan sonar

During the third DISCOL cruise (SO77), deep-towed side-scan sonar was used to map the plough-harrow tracks in the DEA produced during the initial impact phase in February 1989 (SO61). Based on the collected information regarding the level of disturbance it was aimed to differentiate between heavily and slightly disturbed surface layers. Additionally, the depressor was equipped with a photo camera and a depressor to test an integrated method of sonar and optical recording of the seafloor.

Side-scan sonar operates by emitting a narrow beam of high frequency acoustic energy and recording the acoustic return from the seabed (Reynolds International, 2009) to identify different features on the seafloor.

During DISCOL 3 a total of eight deep-towed side-scan sonar surveys were performed. More information on the procedure and initial results can be found in the DISCOL 3 cruise report.

Reynolds International (2009): Side Scan Sonar (SSS) surveying; Technical Summary Sheet No. 16; RIL 09/2009

Schematic display of a deep-towed side-scan sonar operation (Source: Reynolds International)