Knott's equations
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/f0/Reflection_at_an_interface.png/220px-Reflection_at_an_interface.png)
In geophysics, Knott's equations were the first equations to describe the amplitudes of reflected and refracted waves generated at non-normal incidence upon an interface.[1] They were derived in 1899 by the British geophysicist Cargill Gilston Knott using displacement potential functions[2] and describe the same phenomenon that the Zoeppritz equations describe in terms of amplitude displacements.