Seafloor sound-speed profile characterization with non-parallel layering by the image source method: Application to...

Area of Science:

• Geophysics
• Marine geology
• Acoustic imaging

Background:

• The image source method traditionally assumes plane-layered sediments for sound speed estimation.
• Recent advancements extended the technique to handle dipping (non-parallel) sediment layers.

Purpose of the Study:

• To apply the extended image source method to measured reflection data with dipping layers and mud volcanoes.
• To generate a 3D visualization of sediment sound-speed variations in complex geological settings.

Main Methods:

• Utilized an autonomous underwater vehicle equipped with a sound source (1600-3500 Hz) and a horizontal hydrophone array.
• Collected reflection data across a 1 km² area with 3m spacing, covering dipping layers and mud volcanoes.
• Applied the image source method to analyze the collected seismic reflection data.

Main Results:

• Successfully applied the image source method to real-world data featuring dipping layers and mud volcanoes.
• Generated two-dimensional cross-sections of sediment sound speeds.
• Integrated these sections into a comprehensive three-dimensional picture of the subsurface.

Conclusions:

• The image source method is effective for estimating sound speeds in complex, dipping sediment layers.
• The 3D visualization provides valuable insights into underwater geological structures like mud volcanoes.
• This technique enhances geophysical surveying capabilities in marine environments.