Connecting the grain-shearing, creep, and squirt flow models for wave propagation in the seabed

The generalized creep and squirt flow models are shown to be stationary creep processes. A fractional exponent is used to develop a new generalized squirt flow model. The responses of the grain-shearing and generalized creep models are identical, although based on entirely different concepts: a single spring and time-varying damper versus a continuous distribution of parallel Maxwell elements. The random structure of marine sand is more consistent with the latter, implying absence of strain-hardening. The generalized squirt flow model has a high frequency cutoff suited to practical systems, limited by the speed with which underlying physical changes can occur.