MAPPING THE SEA FLOOR USING SIDESCAN SONAR 



Towfish 







Sidescan 



s wa 



th 



In the diagram above, a sidescan- 

 sonar "towfish" is pulled behind 

 a ship, imaging a broad swath 

 of the sea floor. When combined, 

 such swaths form sidescan-sonar 

 "mosaics" or maps of large areas 

 of the sea bottom. The mosaic 

 at left shows depressions (dark 

 areas) floored by sand ripples east 

 of the Farallon Islands between 

 Point Reyes and the Golden Gate, 

 and the mosaic at right shows 

 unusual and complex bedforms, 

 possibly ribbons of sand moving 

 over the sea floor. 



Landscape of the Sea Floor 17 



