To understand the strain-dependent shear modulus and damping ratio of 

reconstituted pumice sand samples, a series of dynamic deformation tests was performed using hollow cylindrical torsional shear test apparatus. The effects of confining pressure level and grading characteristics (or fines content) were investigated, and sieve analyses were performed after each test to check if particle crushing occurred. The results showed that the dynamic deformation characteristics of pumice sands were comparable with those of hard-grained sands, e.g., initial shear modulus and shear modulus ratio increased and damping ratio decreased with increase in confining pressure. The effects of fines content were consistent with those observed in other volcanic soils, e.g. Shirasu in Japan. Under undrained cyclic loading, reconstituted pumice sands did not undergo significant particle crushing, resulting in trends in strain-dependent modulus and damping ratio which were similar to those of hard-grained sands.