138 



EAKTHQUAKES. 



one shock, however, it is quite possible might not be in 

 that of another. We must also remember that a place in 



shadow for a direct 

 ' " ^^ shock might be af- 



fected by reflected 

 waves, and also by 

 the transverse vibra- 

 tions of the direct 

 shock. These effects 

 are over and above 

 the effects produced 

 by the waves of 

 elastic distortion just 

 referred to. It might 

 be asked whether 

 whole countries, like 

 England, which are 

 but seldom s]jaken, 

 are in shadow. 



Destruction due 

 to the interference of 

 'W^a'^es.— Eeferring to 

 the section of the 

 ground at Yokohama 

 (Fig. 27), it will be 

 seen that both the 

 settlement and the 

 bluff stand upon beds 

 of gravel capping 

 horizontal beds of 

 grey tuff. The gravel 

 of that portion of the 

 settlement on the 

 seaboard originally 



