BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 34. pp. 661-668 December 30. 1923 



SOME CEITEEIA USED IN EECOGmZING ACTIVE FAULTS - 



BY STEPHEN TABER 



{Presented before the Society December 29, 1922) 



CONTENTS 



Page 



Introduction 661 



Criteria used in recognizing active faults 661 



Physiographic evidence of recent faulting 662 



Origin of small fault troughs found along active faults 666 



iN^TPtODUCTION 



A fault, once formed, long remains a plane of weakness, and stresses 

 developing in the adjacent region are more likely to be relieved by adjust- 

 ments along it than by the formation of new faults. This is especially 

 true of faults that persist for long distances. The identification of active 

 faults is of importance, since they are the loci of earthquakes, each new 

 displacement of a growing fault resulting in an earthquake. 



Criteria used in recognizing active Faults 



The criteria that have been used in recognizing active faults are: (1) 

 the recurrence of earthquakes along faults, and (2) physiographic and 

 geologic evidence of recent displacement; but each of these may be mis- 

 leading unless the general stability of the entire circumjacent region be 

 taken into consideration. 



The Charleston earthquake of 1886 was one of the greatest recorded 

 in North America, and aftershocks have continued in its epicentral area 

 down to the present day, yet there is no physiographic or geologic evi- 

 dence that crustal movements are going on more rapidly there than else- 

 where in the Atlantic Coastal Plain. Therefore, disastrous earthquakes 

 are no more to be expected in South Carolina than in other States of 

 equal stability, such as Florida or New Jersey. 



* Manuscript received by the Secretary of the Society January 14, 1923. 



(661) 



