l899-'00 TRANSACTIONS 1 25 



of mountains, volcanic action is frequent, whilst the earthquakes 

 originate on the lower portions of the face and base of these dis- 

 tricts. Districts where earthquakes, often followed by sub-marine 

 disturbances are most frequent, are regions like the north-east 

 portion of Japan and the South American coast between Valpar- 

 aiso and Iquique. Here we have a double folding, the seaboard 

 as it approaches the shore line, instead of rising gradually, sinks 

 downwards to form a trough parallel to the coast, after which it 

 rises to culminate in mountain ranges. The South American 

 trough which lies within 50 or 60 miles of the coast, like the 

 Tuscarora deep off Japan, attains depths of over 4,000 fathoms, 

 and the bottoms of these double folds are well known origins of 

 earthquakes and sea waves. 



The general conclusions at which we arrive are that the major- 

 ity of earthquakes, including all of any magnitude, are spasmodic 

 accelerations in the secular folding or creep of rock masses ; a 

 certain number, particularly those originating off the mouths of 

 great rivers like the Tonegawa in Japan, may result from sudden 

 yielding in the more or less horizontal flow of deeply seated ma- 

 terial, the immediate cause of which is overloading by the deposi- 

 tion of sediments ; whilst a few which are comparatively feeble 

 and shake but limited areas, are due to explosions at volcanic 

 foci. 



It will then be abundantly evident that Seismology is intima- 

 tely connected with geology, with the building up of the land 

 areas and mountains and conversely their subsidence below the 

 waters. The aim of seismology is to discover something further 

 regarding the hidden depths of the globe, knowing that any 

 knowledge gained must be of value — and moreover it is evident 

 firom what has already been learned that a knowledge of the 

 depths of the ocean subject to seismic disturbance may be of in- 

 calculable value to countries from whose shores cables radiate to 

 far off lands. 



For many years there has been a section of the B. A. A, S. 

 interested in the investigation of earthquake phenomena, and the 

 committee of this section has of more recent years had new life 

 infused into it by various scientific gentlemen who have resided 

 in Japan. More than twenty years ago, when the Japanese de- 

 cided that their country must be a progressive and up to date 



