# Dictionary:Spherical divergence

{{#category_index:S|spherical divergence}}
**1**. The decrease in wave strength (energy per unit area of wavefront) with distance as a result of geometric spreading. A spherical wave traveling through the body of a medium continually spreads out so that the energy density decreases. For a point source the energy density decreases inversely as the square of the distance the wave has traveled; this means that the amplitude deceases linearly with the distance traveled. For energy which travels along a surface, the analogous term is **cylindrical divergence**, where the energy varies inversely as the distance and the amplitude as the square root of the distance. Other mechanisms by which a seismic wave loses energy involve absorption and loss at interfaces by reflection (including diffraction, mode conversion, and scattering). **2**. The decrease in field strength (flux density) for gravity, magnetic, and similar fields where the intensity decreases as the square of the distance.