1.4 Preprocessing/Trace Editing Seismic data entering this processing sequence must be preprocessed. The data may be in any trace order. Files and traces flagged on the observer sheets as being anomalous (bad) should be deleted prior to the SCAC suite. The process uses the trace balance factors from the trace headers to approximate the conditions present when the trace was recorded. If no trace balance factor exists in the trace header, a value of zero is assumed. If the amplitude measurement is being computed for a data set that is trace balanced and one trace is recorded with much higher amplitudes, trace balancing reduces the amplitudes of this anomalous trace and the amplitude measurement does not stand out. Since the trace balancing factor is taken into account, the amplitude measurement is increased by the trace balance factor for each trace. Note Other trace amplitude modifying routines, such as a data adaptive gain, must not be applied before the SCAC sequence.