800 



NAFE AND DRAKE 



[chap. 29 



Table 



Clayey med. silt 



Cont. border 

 land 



100 



1.506 



" <f>= — log2 (grain diameter in millimeters). 



* Over 50 to 450 c/s range — 0.12/ for vertically traveling compressional wave in dB per thousand 

 feet and over 20 to 125 c/s = 1.0/ for horizontally traveling shear waves in dB per thousand feet. 



