Liu and Sen propose a new general and efficient scheme, which uses a weighted combination of two-way wave equations and one-way wave equations in the damping area, to absorb edge reflections in numerical solutions of wave equations. The results from finite-difference, pseudo-spectral and finite-element modeling show nearly perfect absorption so that this scheme can be applied to solve a wide variety of wave-propagation problems.

Haines and Ellefsen present a pair of case histories demonstrating the use of shear-wave seismic reflection methods to characterize unconsolidated sediments in the near surface. They employ sledge-hammer sources and simple processing flows to create reflection sections that show stratigraphy of the shallowest 70 meters.

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