Lateral changes in recording conditions often require that trace amplitudes be balanced, with consequent loss of information on the lateral amplitude variation of reflected energy. We present a quality-control and automated editing algorithm that recognizes source and geophone coupling problems and different noise levels along the survey line. Problem traces are discarded, and true-amplitude stacking of the remaining ones is possible with constant scaling factors. Application of the algorithm to one of the Vancouver Island LITHOPROBE profiles gives a nominal signal-to-noise improvement of 15 dB and a better understanding of recording problems in the field. Our analysis shows that the varying strength of a reflection from near the top of the subducting Juan de Fuca plate cannot be explained by changing recording conditions alone. Results suggest that the extra effort involved in the automated optimization of common midpoint stacks of low signal-to-noise deep seismic data is warranted only if lateral amplitude information is to be preserved.