Use of lamb and SH attenuations to estimate cement VP and VS in cased borehole

A method of determining properties of a bonding material disposed outside of a casing in a borehole includes at least two of the following three pairs of operations: (1) inducing an acoustic wave in the casing, and measuring attenuation of the acoustic wave, by pulse-echo or other cement bond logging measurement; (2) inducing an SH wave in the casing, and measuring attenuation of the SH wave; and (3) inducing a Lamb wave in the casing, and measuring attenuation of the Lamb wave. (2) and/or (3) may be performed by an electromagnetic acoustic transducer. The method further includes determining the shear velocity or shear impedance and the compressional velocity or compressional impedance of the bonding material based on appropriate ones of the measurements. The bonding material may be cement.