Finite-Element Modeling of the Blockage and Scattering of LG Propagation
Annual rept. 1 Dec 1992-30 Nov 1993
HENRY KRUMB SCHOOL OF MINES NEW YORK ALDRIDGE LAB OF APPLIED GEOPHYSICS
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The problem of Lg wave blockage is being investigated using finite element models of island margin, basin, and basin with an uplifted Moho to simulate wave propagation across the Barents Sea basin. Results from the first year follow. The efficiency of the crust as a Lg wave guide strongly depends on the frequency content of an impulsive source. The effects of a basin on Lg propagation also depends on the basin width and the velocity contrast between the sedimentary basin and the surrounding graniticbasaltic crust. For a high velocity contrast, the Lg wave form is significantly lengthened. The presence of an uplifted Moho alone does not appear to have a major blockage effect on Lg wave propagation. The finite element codes with the fast execution algorithm prove to be well suited as tools for the modeling purposes intended in this research.