110 



Scientific Intelligence. 



II. GEOLOGY. 



1. On Earthquakes in Calif ornia from 1812 to 1855 ; by J. B, Trask? 

 (Proc. Cal. Acad. Nat. Sci., vol. i, p. 80.) — In preparing this paper I have 

 endeavored to obtain, as far as possible, the most correct information of the 

 history of these phenomena in former years, and to correct some of the 

 misapprehensions and statements which have appeared from time to time 

 relating to the severity of earthquake shocks in this country during the 

 earlier periods of its history. 



From careful inquiry of the older residents, I can learn of but one 

 shock that has proved in the slightest degree serious, causing the destruc- 

 tion of either life or property to any extent. This was the earthquake of 

 September, 1812, which destroyed the Mission San Juan Capistrano, in 

 Los Angeles county, and that of Viejo, in the valley of San Inez, in the 

 county of Santa Barbara. 



The following is the history of that event as I have obtained it from 

 the native inhabitants, and older foreign residents on this coast : 



The day was clear and uncommonly warm ; it being Sunday the peo- 

 ple had assembled at San Juan Capistrano for evening service. About 

 half an hour after the opening of service, an unusually loud, but distant 

 rushing sound was heard in the atmosphere to the east and over the 

 water, which resembled the noise of strong wind, but as the sound ap- 

 proached no perceptible breeze accompanied it. The sea was smooth and 

 the air calm. So distant and loud was this atmospheric sound that sev- 

 eral left the building on account of it. 



Immediately following the sound, the first and heaviest shock of the 

 earthquake occurred, which was sufficiently severe to prostrate the Mission 

 church almost in a body, burying in its ruins the most of those who re- 

 mained behind, when the first indication of its approach was heard. 



The shock was very sudden and almost without warning, save from the 

 rushing sound above noted, and to its occurrence at that moment is to be 

 attributed the loss of life that followed. 



The number reported to have been killed outright, is variously esti- 

 mated from thirty to forty-five, (the largest number of persons agree on 

 the smallest number of deaths given), but in the absence of records such 

 statements should be received with many grains of allowance, where 

 memory alone is the only means left, and the term of forty-three years 

 has elapsed to the period at which this account was placed on paper. A 

 considerable number are reported to have been badly injured. 



There is a universal agreement on this point, viz : that the first shock 

 threw down the entire building, and that a large number of persons were 

 in it at that moment, and under the circumstances it would be most sin- 

 gular if no deaths were caused by such an event. 



The motion of the earth is described as a lifting vertically, attended 

 by a vortical movement. No undulatory motion is described by any one. 

 Dizziness and nausea seized almost every person in the vicinity. 



A heavy, loud, deep rumbling, accompanied the successive shocks that 

 followed, which were five in number, all having the motion above de- 

 scribed, though comparatively light in their effects to the first. The sounds 

 attending the phenomena came apparently from the south and east. 



