160 



Subsurface Geologic Methods 



FAULTS 



Fault, showing dip 

 (Dashed where approximately located) 



Barbs on dip symbol 

 may be omitted if pre- 

 ferred. 



Vertical fault 



Concealed fault 

 V 



Doubtful or probable fault 

 (Dotted where concealed) 



Question mark indicates 

 uncertainty as to 

 existence of fault 



Fault, showing bearing 

 and plunge of grooves, striations, 

 or slickensides 



Plunge measured in 

 vertical plane. 



High angle fault 

 (U, upthrown side; D, downthrown side) 



Normal or reverse 

 fault. 



Fault, showing relative 

 movement 



Fault, showing bearing 

 and plunge of relative 

 movement of downthrown block 



Normal fault is shown.) 

 Reverse fault would 

 appear thus: 



Thrust or low angle reverse fault 

 (T, upper plate) 



Normal fault 

 (Hachxires on downthrown side) 



Thrust or reverse fault 

 (Saw-teeth on side of upper plate) 



., # 



Fault zone or shear zone, 

 showing dip 



<•« ;;•. 



Fault breccia 



For use on special 

 tectonic maps only. 



Suitable also as an 

 overprint for 

 mylonitized zones and 

 broad areas of fault 

 breccia. 



