14 EARTHQUAKES ON THE PACIFIC COAST 



The number of shocks recorded at San Francisco in the sepa- 

 rate months (1850-1887) are: 



C January 25 



Ti, . ^ oc r 63, near Vernal Equinox. 



March 36 v .t^ • a ^ 



April 15 j (Rainy Season.) 



T i„/ 47, near Summer Solstice. 



June 17 V ' ,T^ o \ 



July 13 f (Dry Season.) 



„ i , c,-, ( 67, near Autumnal Equinox. 



September ... .31 V ,-n c ^ 



^ ' (Dry Season.) 



October 35 



November. . . .30 

 December . . . .22 

 January 25 



77, near Winter Solstice. 

 (Rainy Season.) 



Kainy season, 140; dry season, 114. Shocks in San Francisco 

 are considerably more frequent in the rainy season than in the dry, 

 contrary to the rule for the State at large. The average number of 

 shocks per month is ff- January, March, October and November 

 have decidedly more shocks than the average; April, July and August 

 have decidedly fewer than the average. 



A comparison of the monthly totals for San Francisco and for 

 California (excluding San Francisco) seems to indicate that the 

 causes of most San Francisco earthquakes are local and not gen- 

 eral in their nature. The records from which this table has been 

 derived are so full that considerable weight must be allowed to 

 the conclusions drawn from it. 



As San Jose is situated near to Mount Hamilton, where accurate 

 earthquake observations will be carried on for many years to come, 

 it is desirable to examine the earthquake records for San Jose and 

 Santa Clara as carefully as may be. 



