RANDOMLY GENERATED PLANE WAVE 



b b 



b b b b " b " b " " b b 



3.0- 



o 2.0 - 



"^--^ 



-1-0 i — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I— 



20 40 60 80 100 120 140 160 



AZIMUTH (degrees) 



- O 



-., Q 



ui 



180 



Figure 6-3 Distribution of spectral parameters versus azimuth of samp- 

 ling for theoretical surface shown In Figure 6-1. The 

 upper series represents the slope of the spectrum In log- 

 log space and varies randomly around the theoretical value 

 of -1 as predicted by theory. Near 0° and 180°, the esti- 

 mates become unstable due to poor sampling. The lower ser- 

 ies represents the intercept of the spectrum in log-log 

 space (or the coefficient of frequency) and agrees well 

 with the sinusoid model predicted by theory. Notice the 

 maximum intercept, and therefore total spectral energy, 

 corresponds to a sample taken perpendicular to strike 

 (azimuth = 90°). 



85 



