Geologists describe the process of an earthquake as occurring in three distinct phases. During the interseismic phase, strain builds up along a fault as adjacent pieces of crust catch onto one another and move in opposite directions. This strain eventually reaches a breaking point, initiating the coseismic phase, in which the crust gives way and "snaps" to a new position. This snap is what we experience as an earthquake. Additional deformation occurs during the postseismic phase, which can last from minutes to years, as the crust relaxes and returns to the interseismic phase.