Abstract: CMP reference surface, i.e. a R_G line of two dimensional seismic profile, is a time domain reference surface induced by two-step correction of seismic data processing. This paper presented theoretically the formulae for calculating corresponding elevation to common midpoint (CMP) reference surface from the procedure of static correction computation of seismic data processing. It is concluded that CMP refer-ence surface corresponds to a flattened plane of static correction starting-point elevation in RG calculation, that is, CMP surface is of a cer-tain elevation signification.

Key words: time domain, reference surface, CMP, static correction