1. n. [Geophysics]
The angle of incidence according to Snell's law at which a refracted wave travels along the interface between two media. It can be quantified mathematically as follows:
sin θc = V1 / V2,
where
θc = the critical angle
V1 = velocity of the first medium
V2 = velocity of the first medium, which is greater than V1.
See: angle of incidence, critical reflection, head wave, refraction, refractor, Snell's law
