EARTHQUAKES: THEIR CAUSES AND EFFECTS. 



By EDMUND OTIS HOVEY. 

 (Read April 24, 1909.) 



The occurrence of three earthquakes in the western hemisphere 

 within the space of nine months in 1906— 1907, all of which were 

 attended with disastrous effects upon human life and property, at- 

 tracted as never before the attention of the world, and particularly 

 of the United States, and focused interest upon the science of 

 seismology in a manner calculated to advance materially the study 

 of movements and other physical changes in the earth's crust. San 

 Francisco, in April, 1906, Valparaiso, in August, 1906, and Kingston, 

 in January 1907, attracted wide notice, but the disaster that over- 

 whelmed Messina, Reggio and vicinity on December 28, 1908, 

 capped the climax, and sufficient reason is apparent for the universal 

 interest now prevailing, one manifestation of which is the present 

 symposium. The thesis of the seismologists is that the chain of 

 earthquake observatories that have been established in the past 

 decade and a half should be extended and united into a network 

 of stations covering the globe, sufficiently, at least, to furnish a com- 

 plete record of the important vibrations propagated through the 

 earth, indicate their places of origin and provide data for more 

 satisfactory theories as to their causes. 



Great earthquakes rank with volcanic eruptions as being the 

 most terrifying of all natural phenomena. Usually coming with no 

 recognized warning, often happening in the night, extremely indefi- 

 nite as to source, extent and duration, they fill the mind of the human 

 observer with the horror of utter helplessness. They have been 

 far more destructive to human life and property than volcanic 

 eruptions have been, for we have the earthquake shocks of Sicily, 

 1693, with 60,000 victims; Yeddo, Japan, 1703 (200,000) ; Peking, 

 1731 (100,000); Lisbon, 1755 (60,000); Calabria, 1783 (60,000) 

 and Messina-Reggio, 1908 (200,000) ; besides many others, to 



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