SOUNDS CONNECTED WITH THE EARTHQUAKE, 
An interesting manifestation of the earthquake was the sound which was heard by 
many people in connection with the shock. Appended is a tabulated statement of the 
testimony bearing upon this phenomenon, if it may be so called. In this tabulation 
there are recorded 81 observations of people who heard sounds, without segregating 
those which are reported in a summary way as the common experience of ‘‘some,” 
“several,” or “many” persons. Of these, 40 report having heard sounds before having 
felt the shock; 14 report the sound as accompanying the shock or coincident with it ; 
3 heard a sound after the shock; and 19 report having heard unusual sounds at the 
time of the earthquake, without further specification. Besides this, there are 3 reports 
of sounds having preceded after-shocks, one case where the sound was observed to pre- 
cede the second phase of the shock but not the first, and one case where sound was heard 
but no shock was felt. The observations are fairly well distributed over the region 
affected by the shock. Besides these observations of a positive kind, there were many 
cases reported where no sound was heard, altho the people were awake. 
In view of the 40 positive and independent observations of sounds having preceded 
the shock, with, in some instances, specific evidence of actions induced by the sound 
having been engaged in during the interval between first hearing the sound and feeling 
the shock, there can be little question that sound vibrations of the air actually preceded 
the sensible shock. The testimony of the 14 persons who heard the sound during the 
shock does not contravene that of the 40 who heard it before, nor does that of the 19 
persons who do not particularly specify the time relation of the sound to the shock. 
Sounds heard before the shock may well have continued thru the shock and come to the 
attention of less alert people only when the shock was felt. The three observations of 
sounds preceding the after-shocks are corroborative of the 40 referring to the main shock. 
The one case near Alturas, where men in camp heard a sound but felt no shock, is an 
interesting and exceptional, but credible, one. 
The evidence as to the character of the sounds is consistent and uniform. They 
were vibrations low in the scale. This fact suggests an explanation of the failure of 
certain people to hear the sounds when others in the same vicinity observed them. It 
may be that the vibrations in question are below the range of audibility of some people 
and within that of others. With this question in mind, an inquiry was addrest to Prof. 
G. M. Stratton of Johns Hopkins University, in regard to the limit of sound. His reply 
was as follows: 
The lowest limit of sound is so differently given by different investigators that it seems 
clear that individual differences play an important part. The limit is placed all the way 
from 8 to 30 double vibrations a second, and that may represent the range of personal 
variation; but more probably it varies between 16 and 30; and those who think they 
hear as low as 8 are in reality hearing the second partial of that tone, viz.,16d.v. This, 
of course, applies only to the perception of tone; for of repeated shocks at a very low rate 
we can still hear the separate shocks, e.g., puffs or blows, but they do not as yet fuse into 
a continuous tone.! 
Now if it should be a fact that the rumbling sounds which preceded the shock fall 
within the range of from 16 to 30 double vibrations per second, then from the probability 
set forth by Professor Stratton, the auditory organs of some people would be sensitive 
to such vibrations, while those of others would not. 

+ Professor Stratton refers to a chapter on ‘‘Tiefe und Tiefste Téne,” in Helmholtz’s Lehre von der 
Tonempfindungen, where the difficulties of accurate determination and the different things that appear 
in such tones are well set forth, 
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