34 SOUTHERN CALIFORNIA GEOLOGY 



boarded in mesh-like arrangement, and the movements 

 of strain-relief are diminished and distributed ac- 

 cordingly. 



The faults of the second northwesterly-extending 

 group of Southern California are quite different in 

 details of arrangement from those of the same group 

 in the San Francisco region. Instead of being closely 

 spaced within a belt a few miles in width, as at San 

 Francisco, they occur as nine or more widely-spaced 

 master rift-lines upon the land, each separated from 

 the other by less-rifted zones of about twenty-five 

 miles in width, and the whole group distributed 

 throughout a belt of two hundred and fifty miles or 

 more. These rifts in Southern California extend in 

 southeast directions for one hundred and fifty miles 

 from the proximity of the Great Transverse Belt to 

 the Mexican Boundary and from thence on into the 

 Republic of Mexico for indefinite hundreds of miles. 

 Names and locations of the fault lines are given else- 

 where herein. 



EARTHQUAKE DANGERS EXAGGERATED 



The vast majority of earthquakes in California are 

 harmless and most of them take place unnoticed. 

 They are mostly the growing pains of a living world at 

 work. Their percentage of danger is exaggerated and 

 their few casualties disproportionately feared. Of all 

 the so-called "acts of God" — storms, tornadoes, hurri- 

 canes, tidal waves, hot spells, floods and freezes — they 

 have caused less destruction of property and life in the 

 United States of America than any of the agencies 

 mentioned. More people are killed annually from acci- 

 dents to buildings caused by faulty construction than 



