The ¶ and § velocities measured for the stainless-steel core, = 5743 75 m/s and = 3092 22 m/s, are approximately twice the Massillon Sandstone values, which seems reasonable. The measured stainless-steel / ratio is 1.86 .04, which is slightly stiffer than the Poisson solid value of = 1.73, as expected.
The ¶ and § velocities measured for the dry Massillon Sandstone are = 2918 32 m/s and = 1731 99 m/s. This represents an / ratio of = 1.69 .12, which is a Poisson solid to within error bounds. The ¶ and § velocities measured for the saturated Massillon Sandstone are = 3380 78 m/s and = 1744 201 m/s. This represents an / ratio of = 1.94 .25, which is not very Poisson-like, and is similar to the stainless-steel sample, neglecting the pessimistic error bounds. When water fills the pores, its effect is to ``stiffen'' the resulting saturated sample. This has a tendency to increase Ks and hence , compared to Kd and . However, , and the increase in saturated density over implies that will be slightly smaller than . These intuitive predictions are fairly well validated by our lab measurements.