The spectral-analysis-of-surface-waves (SASW) method is a nondestructi
ve testing, method based upon generation and detection of elastic stre
ss waves. The key steps involved are construction of an experimental d
ispersion curve froin data collected in situ, and inversion of the dis
persion curve to determine the stiffness profile. An automated algorit
hm for determining the representative dispersion curve from field data
has been presented in a companion paper. In most applications, the de
termination of the layer moduli are accomplished by using a manual tri
al and error process (forward modeling). Unfortunately, this process i
s rather time-consuming and requires engineering judgement. To improve
this aspect of SASW testing, an automated technique based upon the ge
neral inverse theory is described here. The technique provides a fast
procedure for simultaneously determining shear wave velocity and thick
ness of different layers. In addition, some description of uncertainty
in the determined results is provided.