REFRACTED AND REFLECTED LONGITUDINAL WAVES 



19 



The method of calculating the intensities of reflected waves can be sum- 

 iiuarized as follows. 



1. First we determine the sines of the angles of incidence of the reflected 

 wave under consideration at all the interfaces. 



These angles will vary from point to point along the ground surface 

 unlike the corresponding angles for the head waves. It is best to have sin oCq 



Vn.p 



Fig. 4a. Curves for the coefficient FPP (p) of primary wave formation (A =0.6 



and A = 0.4) 



given and then the angles of incidence of the ray selected will have the same 

 sines at all the interfaces, and these will be determined by expression (4). 



sm (Xi = — -^ sm (Xn , 



(4) 



while the point of emergence of the ray under consideration will lie at 

 a distance r, determined by the formula 



