2025_programme: Matrix-Based Approach for Modeling Transient Wave Propagation in Complex Sedimentary Layers

• Day: June 19, Thursday
    Location / Time: C. THALIA at 11:20-11:40
• Last minutes changes: -
• Session: 15. Seabed Acoustics
  Organiser(s): Megan Ballard, Kevin Lee, Nick Chotiros
  Chairperson(s): Nicholas Chotiros
• Lecture: Matrix-Based Approach for Modeling Transient Wave Propagation in Complex Sedimentary Layers
  Paper ID: 2139
  Author(s): Jiashu Lou, Jun Matsushima, Jiayong Tian, Chun-Feng Li
  Presenter: JIASHU LOU
  Abstract: The propagation of transient waves in the ocean is of significant importance in fields such as military applications and marine seismology. Due to the wide frequency range characteristic of transient waves, their interaction with seabed sediment layers cannot be neglected. Analyzing transient wave signals using forward modeling methods can support in-situ experiments and geoacoustic parameter inversion. However, traditional ray methods face limitations in addressing low-frequency components of wideband transient waves, while numerical simulation methods such as Finite Difference, Finite Element, and Spectral Methods encounter challenges in balancing grid resolution, computational speed, and iterative stability.\nIn order to achieve higher accuracy and computational efficiency in analyzing wideband transient waves and extend their application to more complex layered media, we introduces a novel forward modeling method for transient wave propagation in seabed sediment layers. By incorporating a reverberation matrix R, along with the scattering relationships at layer interfaces and the transmission relationships between layers, the elastic wave solution in multilayered sediments is expanded in the Laplace-Fourier domain as a superposition of generalized ray group integrals. Each integral includes terms of R^N, representing N reflections and transmissions at any spatial point, enabling accurate modeling of complex propagation paths. This proposed method could adjust the dimensions and expressions of scattering and transmission matrices dynamically based on the elastic wave motion and constitutive equations of different theories, where theories such as poroelasticity and viscous-grain-shearing are adopted to describe acoustic wave propagation in sediment layers in order address variations in sediment consolidation. The case study shows that the proposed method could model initial response characteristic of transient acoustic wave propagation in practical marine settings in high precision, which will benefit the summarization of transient wave propagation patterns in complex sedimentary layers, the optimization of numerical analysis models, and the support for in-situ experiments and inversion.
• Corresponding author: Mr JIASHU LOU
  Affiliation: The University of Tokyo;Zhejiang University
  Country: Japan