Overburden pressure, lithostatic pressure, and vertical stress are terms that denote the pressure or stress imposed on a layer of soil or rock by the weight of overlying material. Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface Stress is a measure of the average amount of Force exerted per unit Area. Soil, often typeset as SOiL, is a four piece rock band from Chicago Illinois United States founded by Shaun Glass Tom Schofield Tim King and Adam Zadel In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere
The overburden pressure at a depth z is given by

where ρ(z) is the density of the overlying rock at depth z and g is the acceleration due to gravity. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Standard gravity, usually denoted by g 0 or g n is the nominal acceleration due to gravity at the Earth's surface at sea level p0 is the datum pressure, like the pressure at the surface. This article describes a concept from Surveying and Geodesy. For other meanings see Datum (disambiguation.