STRUCTURAL RESULTS OF FAULTING. 



177 



a straiglit line, the faulted surface will be that which would be generated 

 by the horizontal movement of the logarithmic curve or curves along the 

 «-axis of the equation 



>/=iA {vr" — 1) — X tan S 



and in the case of a double curve in an area of a single rock, or f»f 

 rocks with the same coefficient of friction, this ^--axis will be found at an 

 elevation equal to half the vei'ticiil distance between the asymptotes of the 

 curves. 



Surface produced when the fissure is not a plane. CommOnly, llOWCVer, tllC iuterSCC- 



tion of a fault fissure with the earth's surface is not a straight line, but an 

 undulating or broken one. If we still suppose the original surface of the 

 area a plane, the surface after faulting will be that which would be gener- 

 ated by the movement of the logarithmic curve or curves along the broken 

 or undulating line corresponding to the ^--axis, and this line will be the locus 



I'u;. 10. — Contour map of a faulted .surfaci'. 



of the point of inflection of the double curve. The line corresponding to 

 the .?-axis will then be the intersection of a plane parallel to the original 

 surface of the earth with the surface as modified by the fiiult, and if the 

 original surfice was level, the intersection will be a contour. P^ach inflec- 

 12 c L 



