On Theories of the Origin of Microseisms 



with the root sin 3 = VS... where So = the 

 velocity of these waves. Hence the first curve 



121 



starts at sin )3 = b/S- > 1 and tends asymp- 

 totically to sin /9 = b/S- > b/c. 



0-75- 



0-50- 



0-25- 



Figure 3 



The values of C„, 



(sinpj /2 



(-— ) 



\dsinp/ m 



have been calculated by Longuet-Higgins (1950) and are plotted in fig. 3 against h v/b. In fig. 

 4 the ratio 



-= sinp<cos 2pf— - sin2pj"'^ - 2 cosp 



is shown as a function of sin /3. 



