Head-wave correlations in layered seabed: Theory and modeling.

Area of Science:

• Ocean acoustics
• Seismic exploration
• Geophysics

Background:

• Ocean ambient noise is a rich source of information for geophysical studies.
• Understanding acoustic wave propagation in layered seabeds is crucial for marine exploration.
• Head-wave analysis offers insights into subsurface acoustic properties.

Purpose of the Study:

• To derive travel times and arrival angles of head-wave correlations from ocean ambient noise.
• To investigate head-wave correlations in shallow water environments with layered seabeds.
• To validate the method using simulations.

Main Methods:

• Correlating upcoming and surface-reflected head-wave noise signals received at two hydrophones.
• Calculating head-wave travel times from the time differences of correlated signals.
• Determining arrival angles based on sound speeds in adjacent seabed layers.
• Verifying predictions with simulations for a two-layer seabed model.

Main Results:

• Successfully derived travel times and arrival angles of head-wave correlations.
• Demonstrated that arrival angles are dependent on sound speeds in the seabed layers.
• Validated the accuracy of the head-wave correlation method through simulations.
• Confirmed the method's applicability to layered seabed environments.

Conclusions:

• Ocean ambient noise can be effectively utilized to analyze head-wave propagation.
• The derived travel times and arrival angles provide valuable information about seabed structures.
• This technique offers a non-invasive method for characterizing shallow marine environments.