The aquifer is composed of unconsolidated alluvial deposits. These deposits probably consist of both sedimentary rock and poorly indurated or unconsolidated sediments. Unconsolidated surficial materials may also be given a lithology. Wayne County is underlain by unconsolidated beds of sand, clay and gravel. Alluvial rivers have channels and floodplains that are self-formed in unconsolidated or weakly consolidated sediments. Lithification includes all the processes which convert unconsolidated sediments into sedimentary rocks. Beachrock units form under a thin cover of sediment and generally overlie unconsolidated sand. Unconsolidated and friable sand lies beneath this crust. Braunerden are widespread and frequently occur on unconsolidated parent sand or loess parent materials. Pore water pressure developed in unconsolidated soil and sediment causes liquefaction. Tephra is unconsolidated pyroclastic material produced by a volcanic eruption. A flame structure is a type of soft-sediment deformation that forms in unconsolidated sediments. The result was reduced risk of movement by unconsolidated sediments, including contaminated materials, during seaquakes. Auger drilling is restricted to soil, soft unconsolidated formations, or weak weathered rock. Deglaciation left a substantial amount of unconsolidated sediment.