The travel times of sejsmic body waves, which travel through the interior of the earth, are the most direèily meamurable quantities used in deriving the internal structure of the earth. These are directly related to the veloc ty diaribution in the interior by the WiechertHerglotz equation through their distance derivative, dI/dA. The process of arriving at the velocity distribution using the measured values of travel time and ilownes p, which is defined as dT/A, falls under the purview of invertion. Because such derivations are normally based on a set of data which are incomplete and inaccurate, the derived models are not unique (Raskue and Gilbert, 1967, 68, 70; Dzeiwonski, 1970, Johnson and Gilbert, T The recsdure, which is used to determine the velocity structure in the interior ofthe earth, requires a p(dT/d)- curve over the entire range of A and involves solving the Wiechert-Herglotz equation (Bullen, 1963)