EARTHQUAKES AND SEAQUAKES 



79 



operations of the Tonapah Min- 

 ing District, so that there we 

 may study in all its detail the 

 elaborate pattern of earth mar- 

 quetry (Fig. 71) which for the 

 floor of the Owens valley is as 

 yet denied us. 



The earth blocks adjusted 

 during the Alaskan earthquake 

 of 1899. For a study of the 

 adjustments which take place 

 between neighboring earth blocks 

 during a great earthquake, the 

 recent Alaskan disturbance 



FIG. 72. Map of a portion of the Alaskan coast to 

 show the adjustments in level during the earth- 

 quake of 1899 (after Tarr and Martin). 



FIG. 71. Marquetry of the rock floor 

 of the Tonapah Mining District, 

 Nevada (after Spurr). 



offered the advantage 

 that the most affected 

 district was upon the 

 seacoast, where changes 

 of level could be referred 

 to the datum of the sea's 

 surface. Here a great 

 island and large sections 

 of the neighboring shore 

 underwent movements 

 both as a whole in large 

 blocks and in adjust- 

 ments of their subordi- 

 nate parts among them- 

 selves (Fig. 72). Some 

 sections of the coast were 

 here elevated by as much 

 as 47 feet, while neigh- 

 boring sections were up- 

 lifted by smaller amounts 

 (Fig. 73), and certain 

 smaller sections were 

 even dropped below the 

 level of the sea. The 

 amount of such subsid- 



