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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 precede 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., 16 d.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. [1]

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.

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Another interesting question to which the testimony gives rise is: How do such vibrations reach any locality in advance of the shock? The seismic waves traverse the earth's crust very much more swiftly than sound-waves do the air, so that it is a physical impossibility for sound-waves generated in the air above the seat of disturbance to outreach them. The vibrations observed as sounds must, therefore, be transmitted to the atmosphere by tremors of the ground which precede the larger waves, and which are not otherwise perceptible to the senses ordinarily. These doubtless correspond to those phases of seismic movements which are recorded by delicate instruments and are known as "preliminary tremors."

Noises heard at the time of the shock                                                                                                                                                                
Locality.  Reporter.  Observer.  Kind, direction, time of noise, etc. 
Ferndale  A. W. Blackburn  Same  Accompanying the quake was a rumbling, roaring sound. 
Covelo  E. S. Larsen  Large proportion of residents  Roar just preceding earthquake shock. 
Fort Bragg  O. F. Barth  A man  The wave traveled SW. and a roar accompanied it. 
Mendocino  Wm. Mullen  Same  Unusual rumbling sound like distant thunder, preceding shake, being loudest at commencement of disturbance. 
Albion  J. Coyle  Same  Roaring noise like heavy fall of hail coming from ocean to the west. 
Point Arena  W. W. Fairbanks  Not named  Heavy roaring sound preceded the shock. 
Point Arena Light-house  W. W. Fairbanks  Keeper  Blow came quick and heavy, accompanied by heavy report. 
Upper Lake  C. M. Hammond  A roaring noise past off to SW. 
Upper Lake  C. M. Hammond  Workmen  A noise in the trees as tho heavy wind were blowing thru them; then the rumbling past off to SW. 
Cloverdale  M. C. Bale  Many persons  Rumblings before the shock. 
Healdsburg  H. R. Ball  Same  Attended by great rumbling noise, as thunder. 
Santa Rosa  Miss F. Locke  R. Worthington  Heard roaring. 
Santa Rosa  Miss F. Locke  Mr. Campbell  Heard a great roaring 2 s. or 3 s. before the shock. 
Santa Rosa  Miss F. Locke  Watchman  Heard noise in SW.; then felt breeze; then felt shock. 
Santa Rosa  Miss F. Locke  Mrs. Lloyd  Heard noise; ran to window and opened it; then shock came. 
Santa Rosa  Miss F. Locke  A man  Heard roaring and saw wave of earth 2 feet high. 
Cotati  C. L. Jeffrey  Same  Sound as of a strong wind before shock. 
Tomales  C. L. Jeffrey  A boy  Heard roaring and said, "Oh, there's thunder," before the shock. 
Tomales  C. L. Jeffrey  A farmer  Heard roar from SW. 
Tomales  C. L. Jeffrey  Mr. Goudy  Heard a great roaring sound from SE. 
Point Reyes Station  C. L. Jeffrey  A farmer  Heard roar, then felt wind on my face. 
Olema  C. L. Jeffrey  A dairyman  Heard noise in the ground, got up, then felt shock. 
Bolinas  K. Easton  Same  Rumbling noise preceded one after-shock on April 18. 
Calistoga  Dan Patten  Same  A rushing noise before shock came. 
Napa  T. Hull  Not named  A rumbling, then came shock. 
Alturas  C. B. Towle  Some men in camp  Heard low sound of earthquake, but did not feel shock. 
Redding  L. F. Basset  Same  Noise resembled a passing train; it preceded and outlasted the shock. 
Chico  E. Mayhew  Same  Rumbling sound thruout the disturbance like heavy-laden wagon passing house. 
Willows  A. W. Sehorn  Same  Unusual rumbling sound preceded shock, gradually grew louder, and died away with the shaking. 
Colusa  Fred Roche  Same  Sound like an approaching train coincided with shock. 
Berkeley  Miss F. Locke  Capt. Fire Dept.  Was awakened by roar 5 s. before shock. 
San Francisco  M. C. Erskine  Same  Awake at 5h 10m A.M. Heard a great roaring from NE.; soon the shock came from same direction. 
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San Francisco  T. J. J. See  Lieut. Bertholf and other officers  A low rumbling preceded earthquake. 
Peninsula of San Francisco  R. Anderson  Many persons  Noise accompanying the shock; indescribable noise associated with main shock; immediately after the shock. 
San Mateo  B. A. Peckham  Mr. Maxwell  Heavy rumbling which he took for thunder, from NW., before shock. 
San Jose  Mr. Connell  Same  An undertone, rumbling sound coincided with beginning of shock. 
San Jose  W. S. Prosser  Several good observers outdoors  The noise of the quake came from SE. and died away toward San Francisco. 
Santa Clara  I. H. Snyder  D. Pickering  Sound compared to stampede of cattle. 
(3 mi. west) 
Congress Springs  J. C. Branner  Residents  Shock accompanied by rumbling; aftershocks preceded by sound like a blast. 
Los Gatos  I. H. Snyder  Mr. Land  Premonitory roar came from south. 
Los Gatos  W. S. T. Smith  Same  No sound heard for main shock, but muffled sound heard just before each minor shock. 
Los Gatos  F. H. McCullogh  Same  Sound as of bad storm coincident with first and worst of shock. Later in the day there was a rumbling sound to me (deaf) not unlike a distant detonation. 
Wright, 4 miles south of  L. E. Davidson  Same  Attention first drawn to a slight rumbling noise. 
Glenwood  Miss F. Locke  Different persons  After every shock on April 18 was a rumble like that of artillery. 
Scott Valley (Santa Cruz County)  Miss F. Locke  Mrs. Field  Tremendous roaring in NE. 
Santa Cruz  G. A. Waring  Wharfinger  Rumble before shock. 
Santa Cruz Light-house  G. A. Waring  Keeper  Noise as of a wagon crossing a bridge preceded every quake. 
Wilder's Dairy N. W. of Santa Cruz  G. A. Waring  Not named  Shock preceded by rumbling from south. 
Swanton  G. A. Waring  Not named  Distinct noise as of team crossing a bridge to NW. preceded every shock. 
Ano Nuevo Light-house  G. A. Waring  Keeper  Distinct rumbling preceded shock. 
Pescadero  G. A. Waring  Some people  Noise as of wind preceded the shock. 
Castroville  G. A. Waring  Not named  Shock described as beginning like a subterranean blast. 
Salinas  Bertha M. Abbott  Same  Rumbling noise coincided with shock. 
San Lucas  G. A. Waring  Not named  Sound reported to have been heard. 
Fort Romie  G. A. Waring  Not named  Noise heard after shock. 
San Luis Obispo, 1 mile east of  G. A. Waring  Not named  Great roar heard. 
New Almaden (Hacienda)  G. A. Waring  Not named  Loud noise like thunder traveled northward, distinctly preceding shock. 
Coyote  G. A. Waring  A man  Noise from SE. seemed to pass over him. 
San Martin  G. A. Waring  A man  Heard roar, horse became frightened before shock came. 
Gilroy to Hollister  G. A. Waring  Various persons  Rumble heard all thru region from Old Gilroy and San Filipe to Hollister. One said from SE., another from SW. 
Tres Pinos  G. A. Waring  Not named  Distinct rumble preceded shock at Palmtag's winery. 
Bell's Station  G. F. Zoffman  Not named  Rumble distinctly heard before the shock. 
Paicenes  G. A. Waring  Not named  Distinct noise preceded shock at Cienega Lime Kilns. 
Hernandez  G. A. Waring  Not named  No noise before quake, but report as of blast immediately preceded second (hardest) period of vibration. 
Mt. Hamilton  K. Burns  Same  Sound as of flight of birds simultaneous with shock. 
Calaveras Valley  G. F. Zoffman  R. Ingleson  The two separate shocks accompanied by roaring sound from north. 
Modesto  E. Hughes  Several persons  Roaring or rumbling sound beginning a few seconds before and continuing until end of disturbance. 
Modesto  E. Hughes  Green Bros  Roaring sound just before shock. 
Modesto  E. Hughes  Mr. Elsey  Rumbling sound. 
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Modesto  E. Hughes  A. H. Holtman  Shock preceded by roaring sound. 
Modesto  E. Hughes  H. Hintze  Rumbling sound. 
Stockton  E. Hughes  Some persons out of doors  Dull rumbling sound just preceding shock; some think it emanated from buildings. 
Westley  W. G. Carey  Men sleeping on scow on river  Heard terrible rumbling 30 s. before shock; came out of scow to see what it was, then shock came. 
Conejo  E. Picket  Same  Awakened by noise like locomotive coming at full speed. 
Santa Barbara  J. A. Dodge  Neighbors  Rumbling just before shock. 
Lone Pine, Nevada  G. F. Marsh  Same  Slight rumbling sound like wind blowing. 
Ballarat, Inyo County  D. C. Pickett  Same  Awake and up. First indication of earthquake was low, distant, and increasing roar.