Acquisition and processing pitfall associated with clipping near-surface seismic reflection traces

The processing of clipped seismic traces may produce high-frequency wavelets that can be misinterpreted as reflections in filtered shot gathers and common-midpoint (CMP) stacked sections. To illustrate this effect, a near-surface CMP seismic reflection survey was conducted using two sources to compare the effects of various band-pass frequency filters on clipped traces. An event observed in the clipped data set replicated the frequency of the filter operators applied, similar to the effect of convolving a boxcar function with the filter operator. The anomaly exhibited hyperbolic moveout and imitated a reflection during the processing stages. The hyperbolic event was flattened by NMO corrections chosen for the target reflection, and it stacked in as a coherent event in the final section. Clipped data should be removed or corrected before processing to prevent misinterpreting high-frequency reflection artifacts in trace gathers and stacked sections.