Explains seismic reflection theory and how it is useful for understanding seismic events. Presents the different types of multiples in seismic records, describes how they are formed, how they can interfere with primary reflectors, and explains what processes eliminate them. Identifies specific depositional environments and correlates these to seismic reflection complexes. Relates geologic stratigraphy to seismic data reflection responses. Describes basic refraction theory and key concepts, such as the critical angle, low speed layers, hidden layers and dipping layers. Distinguishes the best uses for mode conversion methods and why the concept of Amplitude Versus Offset (AVO) is important.