STRUCTURE OF OCEAN BASINS 



45 



endeavor has been made to eliminate the effect of 

 the different density in distribution of the earth- 

 quake observatories but it may not have been 

 entirely successful. For example, the Atlantic- 

 Arctic region, on which there have been a few 

 detailed investigations made, may be less active 

 than the map indicates. In the Southern Hemi- 

 sphere, on the other hand, as there have been only a 

 very few investigation.?, many earthquakes of 

 moderate size may have escaped attention. But 

 it is my belief that the difference between the 



bottom of the Pacific Ocean and the surrounding 

 regions is not exaggerated. Our records for recent 

 years have confirmed the indicated relations, the 

 regions with the most epicenters are more distant 

 from us than the quiet regions. 



The following is a list of the charts of the different 

 oceans showing the position of earthquake epicen- 

 ters on the sea floor and on the continental margins: 



1. Chart of the Atlantic Ocean. 



2. Chart of the Pacific Ocean. 



3. Chart of the Indian Ocean. 



