690 



EXPLORATION GEOPHYSICS 



will have the effect of stretching out the chart horizontally and the 6 lines 

 will make a larger angle with the vertical, the increase being greatest for 

 small angles where it is most desirable. This type of chart is shown in 

 Figure 425. 



50* 



0.5 

 1.0 

 1.5 

 2.0 

 2.5 

 3.0 

 3,5 

 4.0 



0.2 0.3 0.4 0.5 0.6 0.7 



0.99 SIN e, 



Fig. 425. — Dip chart. 



Horizontal Distance (H) Chart. — Horizontal distances can be quickly 

 read from a chart constructed from Equation 56. Circles of radius 



— sinh— are drawn with centers at the origin. Radial lines making 



angles with the horizontal axis equal to convenient values of 6 are also 

 drawn. Horizontal distances corresponding to observed values of 6 and T 

 are read as ordinates. A sample of this type of chart is shown in Figure 426. 



0.5 1.0 1.5 2.0 2.5 3.0 



Fig. 426. — Horizontal distance chart. 



3.5 



4.0 T-SECS. 



Illustration of Two-Component Dip Shooting 



There are a number of methods for applying the reflection technique to 

 dip shooting. Differing chiefly in details of application and computation, 

 all these methods obtain much the same results under the same basic 

 assumptions. 



Two field seismograms obtained by shooting two symmetrical split 



