Mud sound speed profile constraints from sub-bottom arrival times

Area of Science:

• Geophysics
• Acoustics
• Sedimentology

Background:

• Understanding sediment sound speed profiles is crucial for geophysical surveys and acoustic modeling.
• Previous methods often lack the precision to accurately constrain shallow sediment properties.

Purpose of the Study:

• To precisely determine the sediment sound speed profile in the New England Mud Patch.
• To establish the relationship between acoustic measurements and sediment characteristics.

Main Methods:

• Utilized arrival times of sub-bottom reflected seismic paths.
• Incorporated co-located direct measurements of the angle of intromission.
• Conducted measurements in March 2017 at the central New England Mud Patch.

Main Results:

• An average sound speed gradient of approximately 6 s-1 was calculated for the upper ~3m and ~9m of mud.
• Gradients of 5 s-1 and 7 s-1 over the upper ~9m were found to be too small and too large, respectively.
• The sand-mud transition interval below ~9m exhibited a steep gradient of approximately 200 s-1.

Conclusions:

• Combined acoustic measurements provide narrow constraints on sediment sound speed profiles.
• The findings offer precise data for acoustic and geophysical interpretations in muddy environments.
• The study highlights the distinct acoustic properties of different sediment layers.