No abstract

Velocity analysis using semblance estimates velocities based on a constant amplitude model for seismograms and does not take amplitude variation with offset (AVO) into account. In the presence of AVO, the constant amplitude model becomes inaccurate, particularly for events which exhibit polarity reversals. An AVO sensitive velocity analysis procedure, which is a generalization of the traditional semblance method, can be devised by giving an offset dependence to the modeled seismograms. Incorporating AVO into velocity analysis requires additional parameters to describe the reflectivity. This results in reduced velocity precision. By introducing a regularization term which provides a controlled suppression of the contributions due to AVO effects, we describe an AVO sensitive velocity analysis algorithm that properly deals with events exhibiting polarity reversals or large amplitude variation with offset.

Numerical simulation can be a useful tool for studying composite media. It is not limited by weak or single scattering assumptions, and it requires only constituent properties and an arrangement of constituents as input. For solid/solid media with octagonal cylindrical inclusions and for typical values of constituent moduli, composite moduli are accurately predicted by two‐dimensional (2-D) analogs of Kuster‐Toksöz formulas. For solid/solid media there is a small but discernable difference between responses of square and those of octagonal inclusions. Coherent reflections are produced by a coherent wave incident at a change in concentration of inclusions, if the contrast between material properties of the matrix and those of the inclusions is sufficient to produce significant scattering, and if the size of scatterers is sufficiently small and their concentration sufficiently large so there is constructive interference between waves originating at adjacent scatterers.

No abstract

Numerical simulation can be a useful tool for studying composite media. It is not limited by weak or single scattering assumptions, and it requires only constituent properties and an arrangement of constituents as input. For solid/solid media with octagonal cylindrical inclusions and for typical values of constituent moduli, composite moduli are accurately predicted by twodimensional (2-D) analogs of Kuster-Toksoz formulas. For solid/solid media there is a small but discernable difference between responses of square and those of octagonal inclusions. Coherent reflections are produced by a coherent wave incident at a change in concentration of inclusions, if the contrast between material properties of the matrix and those of the inclusions is sufficient to produce significant scattering, and if the size of scatterers is sufficiently small and their concentration sufficiently large so there is constructive interference between waves originating at adjacent scatterers.