1909.] THEIR CAUSES AND EFFECTS. 247 



that began at 9:15 P. M. of the thirty-first. In the words of Dr. 



G. E. Manigault, a resident of Charleston, as quoted by Button :^ 



Although the shocks at Summerville excited uneasiness in Charleston, 

 no one was prepared for what followed. ... As the hour of 9:50 was 

 reached there was suddenly heard a rushing, roaring sound compared by 

 some to a train of cars at no great distance, by others again to an escape 

 of steam from a boiler. It was followed immediately by a thumping and 

 beating of the earth underneath the houses, which rocked and sv/ayed to 

 and fro. Furniture was violently moved and dashed to the floor, pictures 

 were swung from the walls and in some cases completely turned with their 

 backs to the front, and every movable thing was thrown into extraordinary 

 convulsions. The greatest intensity of the shock is considered to have 

 been during the first half, and it was probably then, during the period of 

 the greatest sway, that so many chimneys were broken off at the junction with 

 the roof. The number was afterwards counted and found to be almost 

 14,000. 



Apparently there were two maxima, the first of ten seconds 

 duration, the second of six, with an interval of comparative quiet 

 of 22 to 24 seconds. The whole period to be assigned to this 

 destructive double shock is about 68 seconds. 



Another observer states that four severe shocks occurred before 

 midnight and that three others followed at about 2, 4 and 8:30 

 o'clock A. M.^** Afterquakes occurred for months. Twenty-seven 

 persons were killed outright and at least 56 more died from injuries 

 received and exposure suflrered. The money value of the property 

 destroyed was estimated for Charleston alone at between $5,000,000 

 and $6,000,000. Not a building wholly escaped injury. Damage to 

 buildings was greater on the low made ground than on the natural 

 higher parts of the city. 



The occurrence of visible surface waves was so definitely as- 

 serted by so many observers and with such detail of description 

 that the fact of their formation cannot be discredited. The pass- 

 ing of such waves has often been included in the description of 

 earthquakes, but their actual existence had been doubted, on account 

 of the difficulty of explaining their origin. The amplitude of the 

 surface waves in some parts of Charleston is estimated by Button 

 at nearly or quite a foot and the average amplitude for the city at 

 three or four inches. 



° Ninth Annl. Rcpt. U. S. Geol. Survey, p. 231. Washington, 1889. 

 '" Op. cit., p. 217. . 



