THE EARTHQUAKES AXD THEIR RESULTS 341 



Page 



Determined from seismograms 386 



Alaskan time records 388 



The corrected times of origin 390 



Comparison of local time records and seismographic time records .... 390 



Speed of transmission 391 



Disturbance of earth's surface 394 



Area disturbed by 1899 earthquakes 395 



Discussion of maps 395 



Square miles shaken 396 



Relation to other Alaskan earthquakes 397 



Comparison with other great earthquakes 403 



Relation of Yakutat Bay earthquakes to life 405 



Introductory 

 the earthquakes and their results 



The severe earthquakes in the Yakutat Ba}^ region, Alaska, in Septem- 

 ber, 1899, were accompanied by faulting, tilting and warping, by- 

 changes of level along the coast, and by glacial oscillations, some of which 

 are still in progress. These have already been described.^ The earth- 

 quakes themselves, however, were only briefly referred to in the reports 

 publislied. It is the purpose of the present paper to describe these earth- 

 quakes. 



They lasted 27 days — September 3 to 29, 1899 — and included four or 

 five world-shaking disturbances and hundreds of minor shocks. During 

 four weeks there w^as almost constant palpitation of this part of the 

 earth's crust. The shocks were most severe on September 3, 10, and 23, 

 and were great on the 15th, 17th, 26th, and 29th (figure 6). On the 

 10th there were over 50 small shocks and two world-shaking disturbances. 

 The greatest faulting took place on September 10, not September 12, as 

 Dr. G. K. Gilbert^ inferred from an erroneous newspaper report, and 

 probably not September 15, as stated by Comte F. de Montessus de Bal- 

 lore.* 



Seismographs and magnetographs in Canada, Mexico, British Isles, 

 Belgium, France, Netherlands, Spain, Germany, Italy, Austria, Eussia, 



2 R. S. Tarr and Lawrence Martin : Recent change of level In Alaska. Science, N. S., 

 vol. xxll, 1905, pp. 879-880 ; Bull. Geol. Soc. Am., vol. 17, 1906, pp. 29-64 ; Geographical 

 Journal, vol. xxvIII, 1906, pp. 30-42, 



R. S. Tarr : Recent advance of glaciers in the Yakutat Bay region, Alaska. Bull. 

 Geol. Soc. Am., vol. 18, 1907, pp. 257-286. 



Lawrence Martin : Possible ohllque minor faulting in Alaska. Economic Geology, 

 vol. ii, 1907, pp. 576-579. 



» Harriman Alaska Expedition, vol. ill, 1903, p. 23. 



* La Science Seismologique, Paris, 1907, pp. 31 and 415. 



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