8 SOUTHERN CALIFORNIA GEOLOGY 



cence of activity. From these facts it follows that 

 earthquake damage is likely to wax and wane periodic- 

 ally and this periodicity should enter into the estimate 

 of insurance as a business matter." 



5. An ingenious argument that since the last great 

 "snap" occurred in Northern California the next one 

 is due in Southern California and inferentially at Los 

 Angeles.^ 



It should be borne in mind that all of these postulates 

 hinge more or less upon the allegation that the re- 

 surveys of the triangulation points after a long inter- 

 val by the United States Coast and Geodetic Survey 

 showed that the mountains of California on either side 

 of the San Andreas Rift were slidiiig past one another 

 at a rate of twenty-four feet in thirty years. If this 

 allegation, which is the cornerstone of Dr. Willis's 

 structure, should prove to be erroneous, then the 

 remainder of the edifice will tumble. Let us wait 

 and see.2 



■■Dr. Willis, apparently forgetting that he had so earnestly and to us ex- 

 pensively predicted that the next great shock comparable to that of 1857 was 

 to take place in Southern California (inferentially at Los Angeles) along the 

 San Andreas Rift, has later and i-ecently made another prediction that a 

 great shock comparable to that of 1857 would take place on the Cuyama or 

 San Andreas Rift to the north of Santa Barbara and extend into the Great 

 Valley, or possibly as far as the Imperial Valley. 



As I am writing these lines. November 4, 1927, another large seismic 

 disturbance is taking place in California, one of unusual severity, and of the 

 intensity such as Dr. Willis might have anticipated. But it is not at Los 

 Angeles or other places in Southern California, although we felt its vibra- 

 tion, not even on the San Andreas or Cuyama rifts, or in the Great or 

 Imperial Valleys, not north of Santa Barbara, but to the north and west of it 

 many miles. Its epicenter is on the west end of the East-West extending 

 Santa Ynez rift of the Transverse Fault Group, probably in the ocean near 

 Lompoc and was felt from points fifty miles west of Point Arguello in the 

 ocean eastward to Phoenix, Arizona. 



-The supposed facts of these pressure-creating movements, which constitute 

 the very foundations of Dr. Willis's predictions were first set forth in Special 

 Paper No. 106, of the United States Coast and Geodetic Survey, published in 

 Washington, 1906, and are fully given and discussed on a later page. 



