Project Abstract
|
One significant limitation of 3D wavefield simulations is modeling very low seismic velocities in the shallow subsurface. The computational requirements increase exponentially by increasing mesh resolution and modeling low material speeds. We aim to implement the 3D seismic velocity fast-Fourier homogenization (FFH) technique coupled with the SCEC Unified Community Velocity Model (UCVM; Small et al., 2017) software to facilitate efficient computations. The goal is to make easily accessible effective-medium velocity models. Toward this goal we: (1) Installed the 2D homogenization program of Capdeville et al. (2010) in a high-performance computer and ran 2D homogenizations in parallel in 8, 16, and 24 cores. To test the simulations, we used simple models, including a 1D layered model and a model of circular inclusion on a homogeneous half-space. The input models were isotropic, with three parameters characterize every point: density and P- and S-wave velocities. The number of samples necessary to compute the effective media makes the required memory too large to fit a single computer shared memory node in the RAM. Thus, multistage runs divide the domain into smaller sections that can run in parallel. (2) The outputs of FFH are the anisotropic elastic constant tensor and density properties at any domain location. These values should be adapted to the input needed to be read by the wave equation solvers. As such, we are working on installing and testing the spectral element wave-propagation software code package SEM46 to be able to run parallel wavefield simulations using effective media velocity models from FFH.
|