AREA DISTURBED 395 



centimeters), and the waves that followed as about 28 miles long and 17 

 inches high (45 kilometers by 43 centimeters). 



Area disturbed by 1899 Earthquakes 

 discu88i0n of map8 



Figures 3 and 4 show the minimum area within which the earth- 

 quake of September 3 and the great earthquake of September 10 are 

 known to have been felt. The locations of observers are shown by the 

 symbol ( * ). The outer boundaries are indicated by solid lines only 

 where evidence shows that beyond that line the shocks were insensible. 

 Dotted lines are used as boundaries where information is lacking. If 

 much of this area had not been a nearly empty wilderness in 1899 and 

 if the investigation could have begun at once instead of after seven or 

 eight years, many more of the men who were inside or just outside the 

 shaken area might have been found. Their evidence would surely in- 

 crease rather than decrease the areas of sensible disturbances for the sev- 

 eral earthquake shocks. 



Nothing on the maps depends on hearsay evidence. Each symbol rep- 

 resents a reliable observer who has been directly interviewed, or corre- 

 spended with, or who has replied to an earthquake circular or published 

 an earthquake record in some report. 



It is only on the southeast, near Sitka and Sumdum (figure 4) ; on 

 the north, near Dawson, Circle, and Eampart, and on the west, between 

 Seldovia and Kodiak, that even partial outer boundaries Gould be drawn. 

 In other directions the shocks were probably sensible even farther than 

 shown, for they were felt everywhere along a chance line of points of ob- 

 servation like the Klondike trail, to the east of which there were prob- 

 ably no human beings in 1899, 



One reason for incompleteness of data is that at distances of over 250 

 miles these shocks were often so weak as to be imperceptible to persons 

 engaged in one occupation, while to others they were sensible. At Sitka, 

 for example, the great earthquake of September 10 was felt by Bishop 

 Eowe, who was lying down, but not by Doctor Georgeson, who was walk- 

 ing out of doors. Two hundred and fifty miles northwest of Yakutat 

 Messrs. Brooks and Peters, of the U. S. Geological Survey, did not feel 

 the September 3d earthquake, though they heard the boom of avalanches 

 caused by it and at exactly the proper time. These men, though trained 

 scientific observers, did not feel the great earthquake of September 10, 

 probably because they were on the march. These shocks were felt, how- 



