142 TRANSACTIONS. 1906-7. 



judged by their destructiveness to man and his works. This 

 depends on how near or close a city or- habitations are to the rift, 

 where the greatest shaking takes place. Earthquake instruments 

 are, however, oblivious to man orhistoy works, they record simply 

 the working of mother earth; so that the great earthquakes of 

 the seismologist are not necessarily co-incident with the great 

 earthquakes of man. 



In the calamitous earthquake of Valparaiso last 16th August, 

 it is reported that the harbor is now ten feet shallower than before 

 that event, and that the motion was mostly vertical. 



The most noted vertical movement of recent years was the 

 Alaska quake of Sept. 10 and 15, 1899, when the uplift along the 

 Yakutat coast for upwards of a 100 miles was many feet, reaching 

 its maximum in Disenchantment Bay where the land rose 47 feet. 



The last quarter of a century stands out pre-eminently as 

 the most marked in seismic disturbances of which we have any 

 historic record. It began with .that cataclysmic explosion of 

 Krakatao in 1883, noted for the red sunsets that followed for the 

 next two years, due to the suspended dust in the upper regions of 

 the atmosphere. Of the important disturbances we may mention 

 those of Ischia near Naples; Tarawera, New Zealand; Charleston, 

 South Carolina; Mino-Owari, the climax of the ma,ny thousands 

 of shocks in Japan; Alaskan coast already referred to; Saint 

 Pierre in the West Indies; Formosa; Vesuvius; and the recent 

 quakes at San Francisco, Valparaiso and Kingston. It is estim- 

 ated that the loss of life resulting from these disturbances is at 

 least 150,000. 



The question naturally occurs, whether we in Canada have 

 much to fear, or even anything to fear from destructive earth- 

 quakes. Speaking generally, I say no, and this especially for 

 eastern Canada bordering the Atlantic; for we have there not that 

 marked contrast of mountain masses and ocean depths, and our 

 St. Lawrence with its long chain of settling basins in the great 

 lakes carries comparatively little suspended matter to load the 

 ocean bed to produce stresses. When, however, the question is 

 asked, should a severe earthquake happen, where will it 

 most likely occur? Then we are pretty safe in predicting that it 

 will occur along our weakest part of the crust of the earth, and 

 that is, along the Great St. Lawrence and Champlain fault, follow- 

 ing the lower part of our ocean stream, already described as the 

 Hne of the great quake in 1663. As a matter of fact we have more 



