Amplitude Variation with Offset (AVO)

1. Amplitude Variation with Offset (AVO) Theory & Applications

2. Introduction • When a wave encounters an interface, part of its energy is reflected while the other part is transmitted (refracted) to the other medium. • At the interface, a wave of a specific mode (e.g., P-wave) may produce other modes (e.g., SV-wave). • An incident P- or SV-wave produces the following four modes: • Reflected P- & SV-waves. • Refracted P- & SV-waves. • An incident SH-wave produces the following two modes: • A reflected SH-wave. • A refracted SH-wave.

3. VP1 VSV1 VP2 VSV2 Snell’s Law θSVr θPi θPr θPt VP1: P-wave velocity in incident medium VSV1: SV-wavevelocity in incident medium VP2: P-wavevelocity in refraction medium VSV2: P-wavevelocity in refraction medium p: ray parameter θSVt