4 6 8 10 12 



Period for Secondory Peck (s) 



• 400~ 



■ 200 2 



14 16 



60 



•50 



40 



* Z 



"5^5 30 



O c 



o „20 



S o 



n 



Use Left Scale 



(b) Nags Head 

 Tp = 12-13 s 

 105 Cases 



Use Right Scale 



3005- 



400 



6 8 10 12 14 16 



Period for Secondory Peak (s) 



18 20 



Figure 20. Frequency of occurrence and average energy for 

 secondary peaks as a function of secondary peak 

 period at Nags Head, North Carolina, 



46 



