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Page:Popular Science Monthly Volume 70.djvu/397

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a low fence and get into the street in about forty seconds. The increase and decrease of the tremors are so gradual that it is very difficult for an observer to tell just when the shock comes and when it ends. From the majority of the testimony it is evident that in this disaster the movement quickly reached the major climax in about ten seconds, then lessened in intensity for about ten more, then gently swelled to a second and minor climax and disappeared in a total of about thirty-five seconds. While there were apparently. no preliminary shocks at Jamaica, there have been many sequent vibrations of the earth, more or less severe. The press has chronicled one on February 23, which was the strongest since the earthquake, and another one also was noted on March 22. Mr. Maxwell Hall[1] has noticed some eighty shocks after the main shock on January 14 to February 5, several of them shaking the whole island, while others were of local extent. On the early morning of January 28 one small shock awakened me instantly by a slight shaking of my cot in the tent in which we were sheltered. The continuance of the motion gave one a sense of insecurity and unsteadiness, and brought with it a slight tinge of dread and nausea. My first impression upon waking was of a rushing, whistling sound from the southwest; it increased and passed overhead, rapidly lessening and disappearing. It was very similar in sound to the approach and passing of a large flock of ducks flying low. Then from the race-course, only a quarter mile distant and only a short time quieted, came the cries of the frightened negroes and the howls of the numerous dogs with which Kingston is cursed, and the crowing of the many roosters in the trees—as they did about every hour during the night. The shock felt on board the moving Port Antonio train produced a feeling as if the coaches were running upon the sleepers and at the same time swaying so much that it seemed as if they would topple over to the southeast. No damage, however, was done to any of the rolling stock or to the roadbed. In none of the many tunnels was any displacement observed. A man driving on the road suddenly felt his vehicle thrown in an angling position across the road and it seemed difficult for the horse to keep its footing. It was observed, however, that motion sometimes counteracted the vibration of the ground and made the latter imperceptible.

The sketch map (Fig. 1) shows by the isoseismal lines the relative intensity of the shock at Kingston as compared with other places on the island. It has seemed rather strange that the most intense destruction should happen to occur just where a large number of buildings are found. But in the case of Kingston, the gravelly foundation in proximity to the epicenter readily accounts for the destruction.

  1. Personal communication to the writer.