Improved free-surface expression for frequency-domain elastic optimal mixed-grid modeling

Autor: Meng-Xue Dai, Jian Cao, Jing-Bo Chen
Rok vydání: 2016
Předmět:
Zdroj: Journal of Applied Geophysics. 130:71-80
ISSN: 0926-9851
DOI: 10.1016/j.jappgeo.2016.04.010
Popis: An accurate and efficient forward modeling is the foundation of full-waveform inversion (FWI). In elastic wave modeling, one of the key problems is how to deal with the free-surface boundary condition appropriately. For the representation of the free-surface boundary condition, conventional displacement-based approaches and staggered-grid approaches are often used in time-domain. In frequency-domain, considering the saving of storage and CPU time, we integrate the idea of physical parameter-modified staggered-grid approach in time-domain with an elastic optimal mixed-grid modeling scheme to design an improved parameter-modified free-surface expression. Accuracy analysis shows that an elastic optimal mixed-grid modeling scheme using the parameter-modified free-surface expression can provide more accurate solutions with only 4 grid points per smallest shear wavelength than conventional displacement-based approaches and is stable for most Poisson ratios. Besides, it also yields smaller condition number of the resulting impedance matrix than conventional displacement-based approaches in laterally varying complex media. These advantages reveal great potential of this free-surface expression in big-data practical application.
Databáze: OpenAIRE
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