Anelasticity and spherical wave AVO-modelling in isotropic Media

Arnim B. Haase and Charles P. Ursenbach

ABSTRACT

Anelasticity modifies the AVO-response of two-layer isotropic models. When reflection amplitude losses due to attenuation are compensated for by unit reflectivity scaling, AVO-characteristics similar to the elastic situation are found. Q-factor dependence of spherical wave AVO is found to be strongest near critical angles of Classes 1 and 2. This Q-dependence, to some degree, mimics depth dependence of elastic comparisons. Normalized spherical wave Class 3 and 4 responses show a mild Q-factor dependence for the highest attenuation levels modelled at Qp1 = 100. Wavelet stretch of converted wave AVO reflection traces is observed in addition to a phase rotation of all anelastic trace examples when compared to the elastic situation.

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