HI Axial Zone of Volcanic Extrusion 



122 Marginal Zone of Active Extension 



RhI Transform Fault 



£1 Fracture Zone 



-(- Topographic High 



Q Topographic Low 



— ► Direction of Seafloor Spreading 



Figure 3. Schematic plan view of features of all seafloor 



spreading centers (not to scale; Rona, 1984). The linear 

 segments of the spreading axis between offsets at transform 

 faults and other deviations from axial linearity are 

 typically of the order of 10 km long. 



10 



