REVIEWS 
The Cause of Earthquakes, Mountain Formation and Kindred Phe- 
nomena Connected with the Physics of the Earth. By T. J. J. 
SEE. Proc. Am. Phil. Soc., Vol. XLV (1907), pp. 274-414. 
The typical propositions of this paper are the following: 
The dynamical cause of earthquakes and volcanoes probably depends upon 
the explosive power of steam formed within or just beneath the heated rocks 
of the earth’s crust chiefly by the leakage of the ocean beds. (Pp. 276, 277.) 
The internal temperature of the earth is extremely high, with heated rocks 
quite near the surface, while the crust is fractured and leaky everywhere, and 
especially where the depth of the sea is greatest. The sea covers three-fourths 
of the earth’s surface, and earthquakes are found to be most violent where 
the sea is deepest, and volcanoes most numerous on the adjacent shores. Could 
then anything be more probable than to suppose that both of these great natural 
phenomena depend simply and wholly upon the explosive power of steam which 
has developed in the heated rock of the earth’s crust? (Pp. 278-80.) 
The conclusions are as follows, from which the geologist who has some 
accurate knowledge of earthquakes, volcanoes, mountains, and geophysics 
may decide whether he cares to follow up these views in the paper itself: 
1. We have seen that deposits of sediment on the continental shelves could 
not possibly produce anything but the most gradual increase of weight on these 
portions of the earth’s crust; and since such rocks as marble are proved to be fluids 
of great viscosity, and therefore capable of slow secular bending without rupture, 
we may feel sure that any stresses thus arising in the earth’s crust would be relieved 
by gradual yielding, and that no violent earthquake shock could ever arise from 
such a cause. 
2. The theory that earthquakes are due to fracture and slipping of rocks is 
disproved by the great depth (ten to twenty miles) at which world-shaking earth- 
quakes are found to originate, and by virtue of the fact that they come not from 
a point nor from a line, but from an area; and moreover earthquakes follow the 
seashore, seldom occurring far inland, and never in desert countries, though 
abundant in the bed of the ocean. 
3. It therefore follows that earthquakes must depend upon explosive forces 
within or just under the earth’s crust, and frequently spread over a considerable 
area, and the preponderance of disturbances in the sea along the shores of con- 
tinents shows that the forces depend in some way upon the sea water. These 
explosive forces can be best studied in connection with the eruption of volcanoes, 
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