168 SEE— FURTHER RESEARCHES ON [April 24, 



S 6. Additional Phenomena Noticed near the Aleutian, Kiirile 

 and Japanese Islands, and the Antandes. — South of the Aleutian 

 chain, as just remarked, a well-known earthquake belt parallels these 

 islands, and the seismic disturbances occurring there are frequently 

 followed by seismic sea waves of the first class. Soon after a great 

 earthquake the water is seen to be withdrawing from the shore, and 

 after a short interval of time it again returns as a mighty wave 

 sweeping everything before it. Many volcanoes have broken out in 

 these islands and several new islands have been uplifted within the 

 historical period. The Russians long ago connected the earthquakes 

 with the volcanoes in the Aleutian Islands. In later years the 

 exact survey of the sea bottom has shown that it is sunk down into 

 a narrow trough right under the earthquake belt. Just parallel to 

 the trough the islands form a real mountain ridge under water, with 

 only a few of the highest points projecting above the surface as 

 islands. The uplift of these islands therefore denotes the uplift 

 of mountain peaks, some of which have become volcanoes. 



Now if the earthquakes are accompanied by the uplift of islands 

 and the sinking of the sea bottom, as shown by the seismic sea 

 waves, it follows that the uplift of the ridge is connected with the 

 sinking of the adjacent sea bottom. As the ridge is just contiguous 

 to the trench, and the earth is terribly shaken every time these dis- 

 turbances occur, it seems to indicate that matter is expelled from 

 under the trench and pushed under the ridge; so that the ridge is 

 elevated and the trench sinks down correspondingly. This could 

 not occur without the bodily transfer of matter beneath the earth's 

 crust, and the shaking of the earth is due to this expulsion of lava 

 from under the trench, and its injection under the ridge. This is 

 the only possible explanation of the observed elevation of the ridge 

 and the sinking of the trench. In this way the trough near the 

 Aleutian Islands has been gradually dug out. Similar troughs have 

 been formed by earthquakes near the Kurile and Japanese Islands, 

 as we know by the observed depth of the sea, the lay of the earth- 

 quake belt parallel to these islands, and the occurrence of the seismic 

 sea waves, showing that the sea bottom sinks after the earthquakes 

 by which the region is afflicted. If the islands of Japan were dug 

 off and thrown into the Tuscarora Deep, they would about fill it up. 



