208 C. Davison — On Earthquake- Sounds. 



IV. — On the Nature and Origin of Earthquake-Sounds. 



By Charles Davison, M.A. ; 

 Mathematical Master at Eing Edward's High School, Birmingham. 



THE sound-phenomena accompanying earthquakes have not often 

 been made the subject of special investigation ; and, con- 

 sequently, their value and significance may have been somewhat 

 underrated. I believe that much remains to be done, that many 

 observations must yet be made, before the problem of their origin 

 can be regarded as completely solved ; but the facts already known 

 seem to me sufficient to show that the inquiry is one full of interest 

 and worthy of development beyond that here attempted. 



Nature of Earthquake-Sounds. 



1. Character of the Sound. — The sound is sometimes of so unusual 

 a character that it is difficult to describe it exactly, but generally it 

 more or less resembles one of the following: (1) Thunder — either 

 a clap or a prolonged peal, the rolling of distant thunder, or thunder 

 when it dies away as echoes among mountains. (2) The rumbling 

 of passing carriages, loagons, etc. — driven rnpidly over a hard road, 

 over pavement, stones, a wooden or stone bridge, or under a gate- 

 way, a heavy traction-engine passing, a couch or heavy chair 

 dragged across the floor of a room above, a train rapidly approaching 

 or rushing through a station, the jerking of a train brought suddenly 

 to rest, the rumbling of wagons laden with planks, stones, or heavy 

 casks. (3) The firing of cannon — either one or several in quick 

 succession, a heavy and well-sustained fire of artillery, a distant 

 cannonade. (4) An explosion — a blast in a quarry, a colliery 

 explosion, the blowing-up of a magazine or powder-mine. (5) The 

 fall of heavy bodies — a cartload of stones suddenly emptied, a heap 

 of rubbish shot down, a large quantity of shingle poured on to 

 a house-roof from a great height, the fall of houses, snow sliding 

 down the roof of a house and falling on the ground, an avalanche of 

 snow, the fall of heavy furniture, a signal-post or a heavy mattrass, 

 a cannon-ball rolling downstairs. (6) Wind — a blast or sudden 

 gust, the roar of wind in a storm, wind among trees, the suppressed 

 roaring of wind entering a gorge, a chimney on fire. (7) Miscel- 

 laneous — a hissing noise like that of red-hot iron plunged into water, 

 the rushing of water, the cracking of a wall, a door violently 

 slammed, the breaking of glass, a horse loose in its stall, the muffled 

 rat-a-plan of heavj^ side-drums, a burst of applause in a room over- 

 head like what newspapers call " loud and prolonged cheering." ^ 



In a few cases (the breaking of glass, for example, or the rustling 



1 This list, hy no means an exhaustive one, is compiled from 389 accounts, obtained 

 from the third part of Mallet's Catalogue of Recorded Earthquakes (Brit. Assoc. 

 Eep. 1854), Meldola and White's East Anglian Earthquake of 1884, and the notes 

 comnuuiicated to me by correspondents during my study of the British earthquakes 

 of the last three years. Out of the above number, comparisons are made to tlumder 

 in 97 cases, to the passing of carriages, 'etc., in 130, the tiring of cannon in 53, 

 explosions in 45, the fall of heavy bodies in 33, wind in 27, and to various sounds 

 under the last heading: in 14 cases. 



