Optimum seismic velocity estimators

Six ‘optimum’ estimators for the root-mean-square (rms) seismic velocity are given and analyzed by simulation for rms error. Two of the estimators are used to test use of a priori velocity information in a Kalman-type improvement on the time measurements. Parameters varied include centre-point depth (time), a priori velocity variance, and interdelay-estimate correlation. The maximum likelihood estimator is shown to be best when a priori information is relatively good, but a least-mean-square estimator is equally good otherwise.