On: “Estimation of Seismic Noise Structure Using Arrays” by Lacoss et al (GEOPHYSICS, February 1969, p. 21–38)

Abstract

There is a fundamental error in the article “Estimation of Seismic Noise Structure Using Arrays” by Lacoss et al which appeared in the February 1969 issue of Geophysics. The fundamental error is that the authors are attempting to resolve the horizontal phase velocity v into two components [Formula: see text] and [Formula: see text] where it is implied that [Formula: see text] and [Formula: see text]. This is incorrect as can be seen from Figure 1 in which d is the distance of the plane wavefront from the origin, [Formula: see text] and [Formula: see text] are the x and y components, and t is the corresponding time.