March 15th, 11h.—A violent shock was experienced at Sacramento; the wave passed through the counties of Placer, Nevada, El Dorado and Plumas. At Iowa Hill the church bells were rung, also at Sacramento. At the latter place and at Forest City, clocks, in many of the buildings, were stopped. This earthquake extended to the eastern base of the Sierra Nevada. At Carson City it occurred at 10h. 45m. and very violent; goods were shaken off the shelves in many of the stores, and a general panic and stampede prevailed.
November 12th.—A smart shock was felt at Humboldt Bay and its vicinity, but no damage was done.
December 21st, 6h. 30m.—At San Francisco a series of light vibrations of the earth occurred, which continued with but two remissions for the space of half an hour. These vibrations were not perceptible to persons in the building otherwise than by mercurial column, which was equal to seven inches of the barometer, and was the mercury gauge of an air pump that had remained stationary at twenty-four inches for the space of four hours. At this time the column in the gauge began to show much disturbance by oscillating up and down in a very rapid manner without any apparent cause; the stop screws (Faraday’s) were all tried at the moment and found perfectly tight as they had remained for hours previous.
The oscillations were watched carefully by Mr. J. Roach and myself for half an hour, at which time they ceased. The maximum of the mercury column was a fraction over an inch, which was attained through vibrations of one-fourth to one-eighth of an inch rapidly repeated and continuous, and as gradually, through a series of lighter vibrations, the displacement would diminish and the column subside to its former level; this was three times repeated, the column at no time being at rest. The period of time occupied by the column in reaching its maximum of disturbance each time was from eight to twelve minutes. There was no apparent cause for this disturbance, unless it be attributable to a series of light vibrations of the earth occurring in a vertical direction, and to that cause I am disposed to assign it.
The passing of carriages on the street did not affect these vibrations of the column, for they continued in the same manner when those vehicles were not passing. While the oscillations were going on, I took a sledge and struck some half a dozen blows on an anvil block in the workshop, which did not make any perceptible difference in the movements of the column; after it had come to rest, the same experiment was repeated, but the column did not in any manner react to the concussion thus produced.
1861.
During 1861 there has been but one earthquake recorded in the State.
July 4th, 16h. 11m.—A severe shock of earthquake occurred at San Francisco. It consisted of three distinct waves following each other in very rapid succession. Its effects to the east of the city in the San Ramon Valley were more severe. Near the house of Mr. Larabie it opened a large fissure in the earth. In the vicinity of Mr. Porter’s it opened a new spring of water, and a small running stream was also caused near Mr. Hunt’s. For several days after, light shocks were repeated at intervals.