GENERALIZAIIONS CONCERNING EARTHQUAKES 37 



reverberations of the great Frisco shock of 1906 were 

 hardly noticeable here. 



RELATIONS OF FAULT LINES TO DANGER 



The majority of earth shocks of Southern California 

 are supposed to occur at points along certain definite 

 and well-determined fault lines, the locations and his- 

 tories of which are more fully described in a later 

 chapter on the geologic structure. 



Townley has written that "investigation has shown 

 that, except when a building was located right on a 

 fault or very near a fault line, none of the earthquakes 

 of the past 150 years have been strong enough to 

 seriously damage a well constructed building. In the 

 San Francisco earthquake, the steel and concrete class 

 A structures were not seriously damaged and neither 

 were well-constructed brick and frame buildings." He 

 also says, "the San Andreas, San Jacinto and Elsinore 

 faults are, fortunately, so far from Los Angeles that 

 earthquakes originating along them lose much of their 

 intensity by the time they reach the city." 



Willis himself has stated that "if you are on the 

 fault, the danger is extreme. If you are ten or twelve 

 miles away, the danger is very materially less." Cer- 

 tainly the longer distance of Los Angeles from the San 

 Andreas, San Jacinto and Santa Ynez rifts greatly les- 

 sons our dangers from them^. I believe that the statis- 

 tics prove incontestably that the San Jacinto fault line, 

 the nearest point of which is sixty miles from Los 

 Angeles, is the most active fault line in Southern Cali- 

 fornia, and that the seismicity of Los Angeles is com- 

 paratively very low. 



Local shocks sometimes occur in Los Angeles from 



