AND VALPARAISO EARTHQUAKES AND THEIR CAUSES. 



51 



all the great destructive earthquakes of which we have historical 

 records. 



The Valparaiso Earthquake. 



About eight o'clock on Thursday evening, August 16th, not 

 quite four months after the Californian outburst, an equally or 

 more terrible earthquake killed probably 2,000 people in 

 Valparaiso and an adjoining large area of Chile, and wrought a 

 destruction of property, with the great fires following, that is 

 conservatively estimated at some $200,000,000. 



The first and most violent shock was followed by many less 

 severe shocks during the subsequent days and weeks, showing 

 conclusively that this was a great tectonic earthquake. The 

 earth-waves or tremors and vibrations travelled with similar 

 amazing speed as in the case of the Cliarleston and San 

 Francisco shocks, and were recorded 5,000 miles away by the 

 seismographs of the United States Weather Bureau in 

 Washington, D.C., where the earth disturbance lasted several 

 hours, ceasing about midnight. 



Probably the Valparaiso shock originated in rock fracture 

 and displacement on some principal fault plane cutting the land 

 area in parallelism with the mountain ranges and the coast, but 

 inside the shore line. That it was not, as with many earth- 

 quakes, beneath the sea, whether somewhat near to or remote 

 from the shore, is indicated by the absence of any great sea wave, 

 such as is raised by submarine shocks, sometimes rolling over 

 the coast far above the highest tide level. This occasional 

 accompaniment of violent earthquakes, most dreadful in its 

 destruction of human lives, was absent from both these recent 

 Californian and Chilian disasters. 



Previous Seismic Eecords of Chile. 



The west coast of South America has abounded with earth- 

 quakes, mostly of slight effects but rarely very destructive, 

 ever since the earliest coming and settlements of Europeans ; 

 and geologists recognise evidences of the same history through 

 long preceding periods. 



In the tabulation by De Montessus de Ballore, comprising 

 very extensive records of earthquakes throughout the world, 

 and giving a grand total of 131,292 observed shocks, mostly 

 belonging to the last fifty years, Central Chile, from Illapel to 

 Concepcion, including the region of Valparaiso and Santiago, 

 had in forty-four years, from 1836 to 1841 and from 1849 to 



