Elastic parabolic equation solutions for underwater acoustic problems using seismic sources

Area of Science:

• Ocean acoustics
• Seismology
• Elastic wave propagation

Background:

• Current models struggle with elastic ocean bottoms and seismic sources.
• Ray theory and fluid-bottom models fail to predict deep shadow-zone arrivals.
• Accurate modeling requires accounting for elastic bottom interactions and seismic energy conversion.

Purpose of the Study:

• To develop and validate elastic self-starter methods for underwater acoustic propagation.
• To model energy conversion between elastic and acoustic waves in range-dependent environments.
• To investigate T-wave generation and interface wave phenomena.

Main Methods:

• Implementation of compressional and shear wave elastic self-starters.
• Modification of elastic parabolic equation solutions for seismic starting fields.
• Modeling of explosive and earthquake-type sources, including pile driving.

Main Results:

• Compressional self-starter yields acoustic fields consistent with benchmark solutions.
• Shear wave self-starter generates transmission loss levels comparable to explosive sources.
• Modeled down slope conversion for T-wave generation from ocean-bottom earthquakes.

Conclusions:

• Elastic self-starters provide a robust framework for seismic source modeling in underwater acoustics.
• The methods enhance the simulation of complex acoustic propagation phenomena.
• Self-starters offer a valuable tool for analyzing T-wave propagation and interface waves.