Isostasy
![Airy isostasy, in which a constant-density crust floats on a higher-density mantle, and topography is determined by the thickness of the crust.](/Images/godic/202501/21/Airy_Isostasy2952.jpg")
![Airy isostasy applied to a real-case basin scenario, where the total load on the mantle is composed by a crustal basement, lower-density sediments and overlying marine water](/Images/godic/202501/21/Backstripping_and_eustasy_correction2952.jpg")
![Cartoon showing the isostatic vertical motions of the lithosphere (grey) in response to a vertical load (in green)](/Images/godic/202501/21/Local-regional_isostasy_-_flexure,_elastic_thickness2952.jpg")
Isostasy (Greek ísos "equal", stásis "standstill") is the state of gravitational equilibrium between Earth's crust and mantle such that the crust "floats" at an elevation that depends on its thickness and density of underlying roots of the low density of the mountain.