A one-dimensional seismic trace constructed from contrasts in velocity or [[acoustic]] impedance derived from acoustic [[interval transit time|transit time]] logs and/or [[density log|density logs]] from a well. The reflection coefficients calculated (at equal intervals of reflection times) from these values are convolved with a typical seismic wavelet to produce the synthetic seismic trace, which may include time-varying filtering, amplitude, and multiple content. It is an excellent medium to correlate well logs to the seismic field record. Errors in [[integrate|integrated]] [[interval transit time|transit time]] must be corrected by using data from a [[check shot survey]] or by correlation to the field seismic record section.