Abstract：The generation mechanisms and characters of four kinds of side waves, such as side fault-plane wave, on 2-D seismic section are expounded using seismic ray theory together with geological model and real example.The side waves usually occur nn the seismic section that is parallel (or near parallel) to the trend pf geological structure in the area where there are steep formations and steep normal faults dipping against the bed,The side waves are primary reflections whose reflecting locations are different from that of ordinary reflections;therefore,they can not be removed in present conventional 2-D seismic data processing.
