164 EARTHQUAKES ON THE PACIFIC COAST 



The vibrations appeared to be south to north, followed half an 

 hour later by a light shock, and one also at 5 o'clock this morn- 

 ing (VI?, VII?). 



1891. Santa Rosa, October 11. 



The severest earthquake felt here in four years occurred at 10.32 

 o'clock. The oscillations lasted forty-five seconds. A slight trem- 

 bling was perceptible for three or four minutes. 



1891. San Rafael, October 11. 



The most severe earthquake experienced here for years was felt 

 at 10.26 o'clock. The shock lasted about twelve seconds. It was 

 preceded by a dull rumbling noise like a heavy vsragon rolling 

 over the pavement. Two shocks of lesser power were felt this 

 morning about 4 o'clock. 



1891. October 13; Monnt Hamilton; 11:0:30 p. m. (Prof. Holden). 



Intensity II, Eossi-Forel scale. 



Prof. Barnard reports as follovps: " Three shocks of earthquake 

 were felt in rapid succession. Interval between the individual 

 shocks about one and a half seconds. The last of these three 

 w^as the most severe. This occurred at 11.00.09 P. S. T. The 

 shocks were simply quick jerks, and ought to have been powerful 

 enough to wake a person from ordinary sleep." 



1891. October 13; Mills College; 10:38 p. m. 



Prof. Keep sends a very complicated diagram from his seismo- 

 graph, indicating disturbances in all directions. Maximum north 

 and south = 3.0 mm.; maximum east and west := 4.0 mm. 



The above figures are for the actual displacements of the earth. 



1891. October 14; San Francisco; 4:33:23 a. m. 



Felt in all parts of the city. Prof. Davidson says: " The last 

 shake was similar to the one of the 11th instant in its wave-like 

 vibrations. Its greatest force was during the first seven seconds, 

 and its entire duration was ten seconds. Time of beginning, 

 4.33.23 o'clock a. m. Direction of the vibration, north and south." 



Following are newspaper accounts: 



1891. Napa, October 14. 



The earth continues to tremble. Four shocks have been felt here 

 this morning. At 4.30 a. m. the people were startled with quite 

 a heavy shock, and several lighter ones have followed. The 

 damage done by Sunday night's shock is much more than was at 

 first supposed and will amount to several thousand dollars. 

 Many of the people here are so terrorized that they have hardly 

 slept since Sunday evening, and the slightest shock now starts 

 many into the streets." 



