NON-ADVANCING GLACIERS 



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the glaciers of the region ; but there is no reason to expect that the effect 

 would occur at the same time, or to the same degree, in the different 

 glaciers. There are at least three reasons why the effect may vary in 

 time, or in intensity, or in both. Of these, doubtless the most important 

 is the length of the glacier, and in this connection it is notable that one 

 of the smallest glaciers, the Galiano, has already passed completely 

 through a period of advance; and that Atrevida glacier now shows the 

 full effects of the advance, while its longer neighbor, the Lucia, has not 

 been affected, excepting possibly in its upper valley portion. On the 

 other hand, the long Marvine glacier, a far greater ice-stream than the 

 Lucia, has entered on the maximum development of the effects, Avhile 

 some very short glaciers, like the Black, just south of the Haenke, show 

 neither signs of having passed through the period nor of its approach. 



These contrasts, however, may be due to one or both of the other two 

 possible causes for variation in the effects of the earthquake shaking. 

 One of these is the steepness of the valley walls, especially in the snow- 

 field section; the second is the amount of snow available. Obviously 

 there must be great differences in the steepness of the mountain slopes 

 and in the amount of snow available in unstable position ; and, according 

 as these conditions favor or oppose a sudden increase in the neve supply, 

 there will be marked variations in the rate and amount of consequent 

 advance. A possible fourth cause for variation in the effects of the 

 earthquake shaking is difference in intensity of shocks from place to 

 place. While undoubtedly the entire region was severely shaken, it is 

 probable that some portions of the area escaped with far less disturbance 

 than others, and consequently with a much smaller addition to the neve. 



There are therefore adequate explanations for the differences obseiTed 

 in the condition of the various glaciers. Some, quite certainly, will never 

 show the effects of the earthquake shaking; others, which have not yet 

 advanced, may be expected to push forward at a later time. It cannot be 

 definitely predicted when this will occur in any individual case, but from 

 the rapidity with which the advance has swept throughout the entire 

 length of some of the glaciers, it seems probable that the effect of the wave 

 will become manifest within a very short period of time in all cases where 

 the cause for the advance has operated. Therefore it may be predicted 

 that, in all probability, this region will be one of great interest to glacial 

 geologists in the next few years. It is highly probable that Malaspina 

 glacier, for so long a period a nearly stagnant ice-plateau, will become 

 crevassed throughout its entire length, and, advancing along its margin, 

 possibly enter the sea, discharging icebergs both into Yakutat bay and the 



