Creep occurs (secondary compression) after consolidation settlements. We defined consolidation settlement, as that compression during which excess pore pressure exists in the stratum. It is presumed that excess pore pressure is a measurable quantity. In a saturated soil it would not be possible to have any reduction in void ratio without development of excess pore pressure. During creep settlements, the strain rate is so low that excess pore pressure is taken as non-measurable.
Secondary compression is time dependent phenomena. Adjustment of soil skeleton continues for sometime efter the dissipation of excess pore pressure. Perhaps the time span may be the order of 100 years.
Secondary compression may be insignificant for Inorganic soils and may be dominant for highly organic soil deposits.