670 



EXPLORATION GEOPHYSICS 



Teltow, "Zur Deutung der Knallwellenausbreitung an der Trennschicht zweier 

 Medien," Physikalische Zeitschrift, vol. 40, 1939, pp. 289-293. 



REFLECTION METHOD 



The characteristic feature of the reflection method is the measurement 

 of the travel-times of longitudinal waves which have been reflected at 

 subsurface boundaries separating media of different elastic wave velocities. 

 From measurements of reflection times it is usually possible to determine 

 the depths and dips of reflecting horizons and the velocities of the seismic 

 waves. 



V 

 f / 



_ *Y 



if/ 



4000 6000 







_^. 



Fig. 413. — -Ray paths and travel-time curves for rays reflected from a 

 horizontal surface. 



Basis of Reflection Method. — For the purpose of forming an ele- 

 mentary concept of the reflection method, and because of its simplicity, 

 we may consider first the case of two horizontal homogeneous and isotropic 

 media. (In practice this situation is seldom if ever met.) From this 

 assumption it follows that the ray paths are straight lines. Making use of 

 the analogy of geometrical optics, these paths may be conveniently handled 



