This paper generated two comment papers in Geophysics. My replies to these comments are contained in the following:

J. G. Berryman, ``Reply to K. Helbig,'' Geophysics 45, 977-982 (1980).

J. G. Berryman, ``Reply to F. M. Lyakhovitskiy,'' Geophysics 46, 336-339 (1981).