It is proper to state that three minutes four seconds, was the greatest error in time found, and the least was twenty-two seconds:
| Locality. | Lat. | Lon. | Time of shock. | Elapsed Time. | Velocity. |
|---|---|---|---|---|---|
| ° ´ | ° ´ | h. m. s. | m. s. | miles. | |
| San Francisco | 37 48 | 122 25 | 8 13 30 | 0 00 | 0 0 |
| Sacramento | 38 32 | 121 23 | 8 20 00 | 7 30 | 6 6 |
| Stockton | 37 52 | 121 34 | 8 23 00 | 9 30 | 6 5 |
| Tejon | 35 00 | 118 46 | 8 45 00 | 32 30 | 6 0 |
| San Diego | 32 42 | 117 13 | 8 50 00 | 36 30 | 7 0 |
The velocity is given in miles per minute, and by dividing the sum of the same by their number, it will be found that the movement of the wave at that time averages a fraction over 6.2 miles per minute.
The results obtained from the above data approximate closely the deductions of Prof. Bache on the wave which reached our shores and resulting from the earthquake at Simoda on the twenty-third December, 1854, and which will be found in a paper read by that gentleman at the meeting of the American Association for the Advancement of Science, during the early part of last year.
From the facts before us, there can be but little doubt of the direction of the commotion, and that it proceeded from the west, or a little south of that point. The motion of the earth, as described at the different localities at which it was felt, with the motion of the pendulum—which was slightly south of a west line—leads to that conclusion. Time is an important element in aiding us to form correct conclusions regarding these phenomena, and it is to be hoped that our friends in different parts of the State, in reporting the same, will be precise in this particular. Of the incidents attending the shocks, many and varied reports have reached us; it seems to have acted with greater violence in the vicinity of the Tejon Reserve and upper Tulare County than at any other place. It is most remarkable that so small an amount of intensity of force was manifested when the area over which it extended is taken into consideration.
The effects were felt in San Francisco several hours before they are reported to have been observed at any other place north or south. They began here at twenty minutes past eleven, on the night of the eighth, and continued till thirteen minutes past eight the following morning—six shocks occurring in the interval; while to the south, the first shock noticed at the Tejon, was at six hours thirty minutes, on the ninth. In Los Angeles they continued at long intervals through the day until twenty-three hours thirty minutes of the same date. I have learned from persons who were present in Los Angeles at this time, and also at the shock of the fourteenth July, 1855, that the severity of the latter exceeded that of the ninth January last past.
1857.
During the past year there has been rather a frequency in the occurrence of the phenomena of earthquakes; and, with the exception of two, there have been none that were particularly remarkable either for extent of surface affected or severity of action. In one, that of the ninth of January, the greatest extent of surface, and greatest intensity of action was manifest. Its principal force seems to have been expended in the more southerly portions of our State, and in the immediate vicinity of those volcanic (?) vents found at different localities upon the Colorado Desert. It is manifest, however, that this shock and those which preceded it on the night of the eighth, had their origin to the west of our coast, as the times of occurrence of the shock at different localities most fully prove. This matter was fully discussed in my previous paper, “On the direction and velocity of the earthquake of January 9th, 1857,” read before this Society March 30th, which will be found in their proceedings.
The other shock of greatest extent, on the second of September, extended over an area of about two hundred miles, but was marked by no particular severity or injury, except that of fright to those who experienced it.
The whole number that can be authenticated as occurring during 1857, amounts to seventeen, being greater than the number recorded in 1853 and 1856; and it would seem probable from our records that this number is the maximum to which we shall probably be subjected in this State.