176 EARTHQUAKES. 



by movements in the waters. According to the ^ Geogra- 

 phical Magazine ' (August 1877, p. 207), it would seem 

 that out of seventy-one severe earthquakes which have 

 occurred since the year 1500 upon the South American 

 coast many have been accompanied by sea waves. Darwin 

 also remarks, when speaking of South America, that almost 

 every large earthquake has been accompanied by consider- 

 able agitation in the neighbouring sea.^ 



On April 2, 1851, when many towns in Chili were 

 destroyed, the sea was not disturbed. At the time of the 

 great earthquake of New Zealand (June 23, 1855), al- 

 though all the shocks came from the sea, yet there was 

 no flood. The small shock of February 14, however, was 

 accompanied by a motion in the sea. 



To these examples, which have been chiefly drawn 

 from the writings of Fuchs, must be added the fact that 

 the greater number of disturbances which are felt in the 

 north-eastern part of Japan, although they emanate from 

 beneath the sea, do not produce any visible sea waves. 

 They are, however, sufficient to cause a vibratory motion 

 on board ships situated near their origin. 



Another point referred to by Fuchs, as difficult of 

 explanation, is, that the water, when it draws back, often 

 does so with extreme slowness, and farther, in some in- 

 stances, it has not returned to its original level. That 

 the sea might be drawn back for a period of fifteen or 

 thirty minutes is intelligible, when we consider the great 

 length of the waves which are formed. Cases where it 

 has retired for several hours or days, and when its 

 original level is altered, appear only to be explicable on 

 the assumption of more or less permanent changes in the 

 levels of the ground. For example, in the earthquake of 

 1855 which shook New Zealand, the whole southern por- 

 tion of the northern island was raised several feet. 



' Darwin, Voyage of a Naturalist, p. 309 



