SPATIAL PROBLEMS IN GEOMETRICAL SEISMICS 



69 



and 10°), and the position of the normal to the interface on the net is deter- 

 mined by the point A^g- Making both directions coincide with one of the 

 meridians of the net we find the plane of the ray and in this plane we plot from 

 the normal the angle of reflection, which is equal to the angle of incidence. 

 We now obtain the point D. We rotate the tracing paper to its original posi- 

 tion and using the Wulff net we take the co-ordinates (azimuth and angle 

 with the vertical) of the point D. The co-ordinates obtained characterize 

 the direction of the reflected ray. 



The ray which we are to examine after reflection has a direction deter- 

 mined by the co-ordinates (309° and 59°) and suffers an azimuthal devia- 



350 iO 



280 



270 



260 



Fig. 14. Determination of the direction of reflected rays for 30° ray surface. 

 1 — directions of incident rays having azimuths from to 360° at every 10°; 2 — direc- 

 tions of the corresponding reflected rays; 3 — direction of norma] to interface at point of 



incidence of rays. 



