268 



Y. OINOUYE 



II. EFFECT OF THE EARTHQUAKES 



There were several phenomena of interest due to the preliminary 

 earthquakes, such as fissures, faults, and the building of mud 

 cones. 



i. Fissures. — Many ruptures were made within the circle of 

 severe shaking of the earth, especially on the west side of the 



Fig. 12. — South scarp of "graben" at the top of Kompirayama. Taken July 14, 

 1. 



1911. 



volcano. The directions of the fissures were almost parallel to 

 the coast line, i.e., northwest to southeast, and their width was 

 from 3 cm. to 40 cm. (Fig. 2). Close to the mountain, on the 

 west side, the direction changed to east-west. 



2. Faults. — Two distinct faults extending east and west were 

 made on the west foot of the Usu. Stepping down toward the 

 north (downthrow side on the north), the throw of the southern 

 fault measured 30 cm. and that of the northern one 1 m. The 

 former extended about 50 m. and the latter 600 m. in length. On 

 September 2 an additional throw of 1 m. was noticed, developing 



