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Seismic Wave Propagation Finite Difference Simulation Based on Adaptive Mesh Refinement (AMR) Grid

Description: 

Finite-difference method (FD) is widely used for seismic wave propagation simulate because its efficiency and easy-usage. But low velocity basins cause smaller grid spacing to suppress the numerical errors below the required level and cause severe spatial and temporal oversampling, which is one well-known drawback of FD to simulate strong ground motion in complex basin structures. In this work, we adapt adaptive mesh refinement (AMR) grid to acoustic and elastic wave FD simulations. Unlike mesh refinement at shock waves in computational fluid dynamics, we implement mesh refinement according to velocity values of the velocity model: the mesh is adaptive refined in such a way that the grid spacing everywhere satisfies the minimal points per wavelength requirement of the FD scheme. To speed up the development, we did not create the AMR code from scratch but developed the code based on an existing AMR framework AMReX (https://amrex-codes.github.io/amrex/). We successfully implemented AMR with the staggered-grid finite-difference method to simulate 2D acoustic wave propagation and with the collocated-grid finite-difference method to simulate 2D and 3D elastic wave propagation. We used several numerical tests to demonstrate the stability, accuracy and efficiency of the proposed method in strong heterogeneous models. AMR data structure management and overlapping multi-level grid structures also introduce computational overheads. We discussed the factors influencing the computational efficiency.

Session: Numerical Modeling in Seismology: Developments and Applications

Type: Oral

Date: 4/20/2023

Presentation Time: 04:30 PM (local time)

Presenting Author: Nan Zang

Student Presenter: No

Invited Presentation: 

Authors