93 



Dr. Trask read the following paper : 



At the close of 1855. 1 presented to the Associa- 

 tion a statement of the occurrence of earthquakes in 

 this State tor that year and a term of years preceding. 



Daring the year just passed, I have kept a careful 

 record of these phenomena, that have been noticed 

 in this city, aiid other parts of the State, and which 

 will be found below, with their date, and the hour of 

 the day ou which they took place, and they comprise 

 all that have occurred, with perhaps two exceptions, 

 the date for wnicii were so obscure as to render it 

 impossible to determine with accuracy the precise 

 period of their occurrence. So far as I am informed, 

 those shocks which hive taken place in this State 

 during the past year have not been marked with 

 more severity than has been usual in years preceding, 

 frtquently amounting to a slight tremor, and at oth- 

 er times to more distinct movements; three only 

 have possessed sufficient intensity as to command 

 general attention luring the busy hours of day. 



Very few have bjen noticed by persons who were 

 standing upoti the earth at the period of their occur- 

 rence. By far the greater proportion were observed 

 in high situations fnim the ground, and in the more 

 retired parts o f t he city, or on the alluvial covering 

 of the country to the west and south 



The total number for cue p iSC year is sixteen, ami 

 of this number thirteen w. re observed between sun- 

 set and sunsise, a tact sufficient in itself to show the 

 lightuess of their character ; tor, did they possess 

 that severity so often attributed to them, the at en- 

 tion of the populace would much more often be di- 

 rected to their observance. Yet we find sucii is not 

 the fact, their first knowledge of such an occurrence 

 being usually its announcement by the daily press. 



By reference to the statistics below, it will be Seen 

 that even in the mountain districts, where during the 

 day there is much less of turmoil and noise arising 

 from business than in toe populous city, that of all 

 those noticed, uoue have been of sufficient intensity 

 to attract the attention of the inhabitants during the 

 hours of daylight. These tacts, though few in them- 

 selves, are ot importance, to disabuse the public 

 mind in relation to the danger to be apprehended 

 from the occurrence ofthe.se phenomena. The char- 

 acter which we sustain both at home and abroad, as 

 being in constant danger of bein<i swallosved up by 

 these occurrences, and that our country is but a bed 

 of latent volcanoes ready to burst forth at any mo- 

 ment, spreading devastation over the land, is one of 

 the greatest fall icies that ever obtained possession of 

 tli" human brain. Our State is as primitive as Mas- 

 sachusetts or Ne.v Hampshire, and the dangers that 

 attend us from the sources above spoken of, are 

 equally great as in the States, just named. 



We should remember that when speaking of Cali- 

 fornia as a State, that we include a line ot territ.my 

 equalling that of the seaboard lying between Cape 

 Haltera ■ on the south and the British Possessions un 

 the north, and including eleven of the seaboard 

 8ta r es of tne Union ; and when we place our cnmi ar 

 ative estimated on this basis in mai ters of this char- 

 acter, it will become at once evident that the I- ngi r 

 ot annihilation from the c ii-es uud> r consideration. 

 are not of that magnitude that at first sight would 



appear. 



Along tlii: coast, of Mexico and Central America, 

 to the south of California from all the record; that 

 are obtainable here, there appears to have been a 

 much greater exemption from tho-e phem men a ill hi 

 has been usuil in former years; this aeemn to bave 

 been the fact, also, throughout the Pacific, Oceanic 



and most of the Continental islands along the coast 

 of China, while to the north and north-west, beyond 

 the fifty-fifth parallel, both volcanic and earthquake 

 phenomena appear to have been greater than usual. 

 This has been observable, for the most part, in the 

 neighborhood of the Aleutian Archipelago, along the 

 north east coast of Japan, and in the Briiish°and 

 Russian Possessions of North America on the Pacific, 

 and islands of the Ochotsk Sea. 



It would be interesting to know more of the pre- 

 dominance of these phenomena in those regions, and 

 such information could he easily obtained from the 

 commanders of the whaling fleet, if the proper mea- 

 sures were adopted to secure it. 



Below will be found some interesting matter upon 

 this subject, which took place during the past year 

 near the .Straits of Ourinach. The earthquakes which 

 have occurred in this State during 1856, and the pe- 

 riod of their occurrence, is as follows : 



Jan. 2d — At a quarter before ten this morning, a 

 smart shock of an earthquake was felt in San Fran. 

 Cisco. The motion ot the earth was undulatory. and 

 cune apparently from the northward. A pendulum 

 indicated a motion of about, five and a halt inches. 



Jan. '28th. — At the town of Petal uma, Sonoma 

 county, a shock of an earthquake occurred at a 

 few minutes past three o'clock in the morning — 

 It was sufficiently heavy to awake persons from their 

 sleep. 



Jan. 29M. — At a quarter before one o'clock this 

 morning, a slight shock was felt in San Francisco — 

 It was observed also at the Mission Dolores. There 

 were three distinct tremors, with short intervals 

 elapsing hetween. The motion was apparently from 

 the westward. 



Jan. 2lst. — Quite a smart shock occurred at four 

 o'clock this evening ; it was quite sharp in the south- 

 west part of the city. 



Feb.i5th. — At five o'clock twenty-five minutes a 

 Severe shock of an earthquake was felt in San Fran- 

 cisco, the duration of which was a bout eight seconds. 

 I'ersous sleeping were aroiired, and many persons left 

 their beds and sought the street. There were two 

 disiinct shocks, the second very light and scarcely 

 perceptible. The motion was undulatory and vorti- 

 cal, and at the end of the first shock a very strong, 

 profound jar, wi'h which it ceased. 



The upper part of a building on Battery street, for 

 seventy feet in length, was thrown down, the whole 

 of which was above the cornice very thin, and the 

 mortar with which it was constructed had not be- 

 come hardened, being easily removed bv the lingers 

 — it. more resembled wet sand than a firm mortar. — 



There appears but little difference in the sensa- 

 tions of persons situated either in upper or basement 

 stories. 



It was pi eceeded by a deep, heavy rumbling, and 

 the motion apparently came from the northwest. A 

 distinct shock was felt at eight minutes past two 

 o'clock the same morning, by persons who were 

 awake and up at the time. 



The vortical movement was shown in the fact that 

 small square bottles and boxes that stood upon a 

 line, were moved from their position horizontally, 

 describing an arc of thirty degrees .and upwards, 

 as shown by the dust upon the shelves on which they 

 stood, 



t he first wave came with a force sufficient to pro 

 ject small articles three or four feet on the floor, 

 from shelves on which they woe placed ; they were 

 apparently all thrown in the same direction. Seve- 



