22 



THE FLOOR OF THE OCEAN 



FIGURE 9. WORLD MAP ON MERCATOR PROJECTION, SHOWING PATHS OF 



SEISMIC WAVES FROM A SOUTH ATLANTIC CENTER OF SHOCK. 



AFTER J. T. WILSON. 



like those derived from the work of Gutenberg and Richter, 

 with the exception that Wilson found no evidence of any great 

 difference between the average rock under the Pacific ooze and 

 the average rock beneath die Atlantic ooze. There is also con- 

 firmation of the opinion that granitic rock of notable thickness 



Table IV 



VELOCITIES OF A SURFACE-SHEAR WAVE ALONG DIFFERENT PATHS 



Per cent of 

 path con- 

 tinental 



Recording 

 station 



Velocity 

 (km/sec) 



Paths purely oceanic: 



Atlantic Ocean 



Atlantic-Indian oceans 

 Atlantic-Pacific oceans 



Paths mixed: 



Atlantic-Americas 



Atlantic-Africa 



Atlantic-Africa-Europe 



Path across North America 



Path across Eurasia 





 

 



40 



40 



40 



100 



100 



Ivigtut 

 Colaba 

 Honolulu 



Toronto 

 Helwan 

 Stonyhurst 



4.35 

 4.25 

 4.40 



4.05 

 4.05 

 4.00 

 3.70 

 3.53 



