192 



PHYSIOGRAPHY 



it to bound up inches or even feet, though the floor itself moves 

 but a small fraction of an inch. 



While violent earthquakes are among the most terrible of nat- 

 ural phenomena, so far as human affairs are concerned, those of 

 historic times have left few important marks on the surface of the 

 earth. Their destructiveness to human life comes largely from 

 the fall of buildings, and from the great waves caused by the earth- 



Fig. 190 Fault in Japan, 1891. (Koto.) 



quakes. The advance of these waves upon a low coast which is 

 densely populated, has caused great destruction of life in some cases. 

 Thus in the Lisbon earthquake of 1755 a wave 60 feet high swept 

 up on the shore and destroyed some 60,000 human lives. 



Examples. Some of the principal features of earthquakes may 

 be brought out by the study of a few striking examples. 



On October 28, 1891, an earthquake on Nippon, the main island 

 of Japan, opened a fissure traceable for over 40 miles. The ground 

 on one side of this fissure sank 2 to 20 feet (a fault} below that on 

 the other. At the same time the east wall of the fissure was pushed 



