16 EARTHQUAKES ON THE PACIFIC COAST 



The distribution of shocks in the various months is as follows, 

 for: 



January 2 



February ^ ) -, •- ^i -tr i t^ • 



^ , •' p. ( 15, near the Vernal Equinox. 



April .".' '.!.'.'; ^3 f (^^'""^ Season.) 



May 2 i 



T ' 1 / 7, near the Summer Solstice. 



June 1 > /-n o 



July 4J (Dry Season.) 



o °, i" ■ f 17, near the Autumnal Equinoj 



September ... .l I /t-. o \ 



October 9J (Dry Season.) 



15, near the Winter Solstice. 



December ... .5 ^ ,r, • c 



T o I (Rainy Season.) 



January 2 ) ^ ■' ' 



Eainy season, 30; dry season, 24. Like San Francisco, and 

 unlike California at large, San Jose seems to have more shocks in 

 the rainy season. 



The average number of shocks per month is 4^ divided by 37. 



February, October and November have decidedly more shocks 

 than the average; January, May and June have decidedly fewer 

 than the average. July and August have (unlike San Francisco) 

 the average number of shocks. If the data are sufficient to draw 

 any conclusion from (which very probably they are not), this would 

 show that the shocks at San Jose are local, and that they are, in 

 general, not dependent upon the same cause as those of San Fran- 

 cisco. 



Similar tables can be formed for the places where the cata- 

 logue shows shocks to be relatively frequent, as Humboldt, Los 

 Angeles, Oakland, San Diego, Monterey, Santa Cruz, Sacramento, 

 etc., and, so far as the data are sufficient, the same result will be 

 indicated, namely, that the light earthquakes common in California 

 are usually rather local than general and widespread phenomena. 

 A curious example of this is the exemption of Santa Barbara from 

 shocks in the years 1860-1873. Before 1860 and after 1872 Santa" 

 Barbara was subject to shocks, precisely as other places in the 

 same region, while between these years no shock is recorded. 

 There is no reason to believe that the records were not equally well 

 kept during the whole period. 



The immediate and practical conclusion to be drawn from the 

 above tables is that in any future study of California earthquakes 

 we ought to select special regions for examination, as the Valleys of 



