1906 ] 



SEE— THE CAUSE OF EARTHQUAKES. 



297 



Europe, made up throughout of broken mountainous regions ex- 

 tending into the Mediterranean, with the Black Sea and Caspian on 

 the east, are not essentially different from the earthquake regions 

 surrounding the Pacific Ocean. 



In his recent Bakerian Lecture at the Royal Society, March 12, 

 1906, Professor Milne explains his latest classification of seismic 

 regions as follows : 



" Regions which lie on the western snboceanic frontier of the American 

 and the eastern frontier of the Asiatic continents, and regions which lie on 

 a band passing from the West Indies through the Mediterranean to the 

 Himalayas. 



"In addition, to these there are two minor regions, one following the 

 eastern suboceanic frontier of the African continent, which I have called 

 the Malagassy region, and an Antarctic region which lies to the southwest 

 of New Zealand. 



" The following table gives the number of large earthquakes or mass 

 displacements which have occurred in the subdivisions of these regions since 

 1899- 



"Region of the Pacific 

 Ocean. 



Western Atlantic and 

 Eurasian regions. 



1. East Indian Archi- I 



pelago II 



2. The coast of Japan... 19 



3. Alaskan coast 14 



4. Central America 6 



5. West of South Amer- 



ica 



6. Antillian region 



7. Azores 



8. Alpine, Balkan, Cau- 



casian, Himalayan 

 region 



9. Malagassy district 



10. Antarctic district 



9 

 6 



13 



Total. 



75 

 59 

 30 

 28 



16 



25 

 25 



62 

 21 



Between March, 1902, and Novem- 

 ber, 1903, 75 large and small disturb- 

 ances were recorded. 



Totals I 91 56 I 43 64 58 29 341 



" Many of the disturbances included in this table are known to have been 

 followed by hundreds and even thousands of after-shocks. The most active 

 district is at present that of the East Indies, which might well be consid- 

 ered as an eastern prolongation of the Himalayan region. The scene of 

 this activity it may be noticed, is at the junction of two lines of rock folding, 

 which meet almost at right angles. Whether the Antillean and Central 

 American region should be separated is open to question. If we unite their 

 registers as belonging to two comparatively near and parallel earth ridges, 

 the movements of one influencing those of the other, we have a region of 

 hypogenic activity approximate to that of the Japan seas. 



