Underwater noise from on-land blasting

Area of Science:

• Acoustics
• Marine Biology
• Environmental Science

Background:

• Underwater noise from on-land detonations poses risks to marine ecosystems.
• Limited experimental data exists on the acoustic characteristics of this noise source.

Purpose of the Study:

• To quantify underwater noise generated by near-water land detonations.
• To analyze the propagation characteristics of detonation noise into marine environments.

Main Methods:

• Measurements were conducted at Bentinck Island Demolition Range.
• Analysis focused on ground-to-water and air-to-water propagation.
• A wavenumber integration model was employed to study evanescent fields.

Main Results:

• Ground-to-water propagation was identified as the dominant transmission path.
• Air-to-water coupling via evanescent waves was observed, but primarily at close distances.
• The depth dependency of the evanescent field was illustrated.

Conclusions:

• Land detonations generate significant underwater noise, primarily through ground-to-water paths.
• Evancescent wave coupling is a secondary, short-range phenomenon.
• Understanding these propagation mechanisms is crucial for marine mammal protection.