GENERALIZATIONS CONCERNING EARTHQUAKES 51 



Concerning the subject of the possibility of pre- 

 diction of future shocks in Southern California, we 

 also refer the reader to the words of Mr. H. 0. Wood. 

 California's leading authority upon seismology : 



"I desire to state at the outset that the 

 best that I, or any other person, can do in 

 this matter is to form a careful judgment 

 based upon the available facts, which in 

 many respects are scant and ill-coordinated. 

 There is no definite or exact knowledge re- 

 garding the earthquake situation in the fu- 

 ture, here or elsewhere, in the possession of 

 any student of this subject. Competent and 

 reliable men may reach somewhat different 

 conclusions on the basis of such facts as are 

 available. Notwithstanding this, certain con- 

 clusions are warranted, and others are not. 

 In particular, no one can say that a strong 

 or destructive earthquake is certain to occur 

 in Southern California within a definitely 

 specified short interval in the future, nor 

 that such an event is very probable within 

 such a definitely specified short interval. 

 Such a pronouncement is a definite predic- 

 tion — unwarranted in the present state of 

 knowledge — and even if it should be veri- 

 fied by the course of events this at best 

 would only be the confirmation of a shrewd 

 guess. . . ." 



