Detecting submerged bodies: controlled research using side-scan sonar to detect submerged proxy cadavers

Area of Science:

• Forensic Science
• Marine Technology

Background:

• Side-scan sonar is a key tool for forensic investigators in submerged body searches.
• Limited research exists on factors influencing side-scan sonar detection of submerged bodies.

Purpose of the Study:

• To investigate how terrain, body size, sonar frequency, swath width, and decomposition affect submerged body detection using side-scan sonar.
• To provide controlled data for optimizing side-scan sonar deployment in forensic investigations.

Main Methods:

• Controlled experiment using pig carcasses as human proxies.
• Two phases of research varying terrain, carcass size, sonar frequency, and swath width.
• Monitoring detection over an 81-day period to assess decomposition effects.

Main Results:

• Optimal detection occurred on clear, flat, sandy terrain; irregular terrain and vegetation significantly limited detection.
• Higher sonar frequency and a 20m swath width enhanced detection, especially for smaller targets.
• Medium-sized carcasses remained detectable throughout the 81-day study, even during decomposition.

Conclusions:

• Clear, flat, sandy environments are crucial for successful submerged body detection with side-scan sonar.
• Specific sonar settings (frequency, swath width) should be adjusted based on target size and environmental conditions.
• Side-scan sonar remains a viable tool for detecting decomposing submerged bodies over extended periods.