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A staggered-grid finite-difference method with perfectly matched layers for poroelastic wave equations
1Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA.
The Journal of the Acoustical Society of America
|June 27, 2001
Summary
A new finite-difference method simulates elastic waves in complex media. This technique effectively detects buried land mines by analyzing distinct acoustic wave responses in sand and mud.
Area of Science:
- Geophysics
- Computational Seismology
- Poroelasticity
Background:
- Simulating elastic wave propagation in heterogeneous poroelastic media is crucial for geophysical exploration and subsurface imaging.
- Traditional methods often rely on second-order differential equations, which can be computationally intensive and less accurate for complex media.
Purpose of the Study:
- To develop and validate a novel finite-difference (FD) method for simulating elastic wave propagation in multidimensional heterogeneous poroelastic media.
- To apply the developed method to investigate the interaction of elastic waves with buried land mine-like objects in various soil conditions.
- To assess the feasibility of using acoustic measurements for buried object detection.
Main Methods:
- A first-order hyperbolic leap-frog system derived from Biot's equations was employed, offering high accuracy.
- The system was discretized on a staggered grid in both time and space for enhanced numerical stability.
- A perfectly matched layer (PML) absorbing boundary condition was implemented to minimize artificial reflections from computational domain edges.
Main Results:
- The numerical method was validated against analytical solutions, demonstrating its accuracy and reliability.
- Simulations of elastic wave interaction with a buried mine-like object showed significantly different wave responses in dry sand, sand, and mud.
- The study confirmed that processed acoustic measurements can effectively detect the buried target.
Conclusions:
- The developed FD-PML method provides an accurate and efficient tool for simulating elastic wave propagation in complex poroelastic media.
- Distinct acoustic signatures generated by buried objects in different soil types can be utilized for detection purposes.
- This research offers a promising approach for non-invasive detection of buried targets using seismic and acoustic methods.