So far we have said nothing about submeridional dislocations, a type which includes, in particular, the dislocations bordering upon the Pacific Ocean, which play a leading role. The distribution of these dislocations was described in my recent book (1960). In the Northern Hemisphere such dislocations are distributed symmetrically over the body of the planet, at 90° intervals; they include the Cordilleran Ranges, the Mid-Atlantic the Ural-African Graben, and the Kuril-Japanese Range.
As I see it, in the Southern Hemisphere this antipodal character of the critical meridians is disturbed somewhat, since the distribution Of the continents (in relation to their antipodal character relative to the ocean) is different; here the distribution is somewhat otherwise than in the north. Katterfel'd and Spitaler think that even here there is a symmetrical distri bution of the dislocations along the meridians. According to Spitaler, the four meridians to which the mountainous belts are confined are the critical meridians. Like the critical parallels, they characterize the symmetry of the Earth, and their properties are determined by a distri bution of stress zones which is nearly latitudinal. Obviously, if the critical parallels are associated with meridional stresses, in the present case we have to do with the effect of latitudinal stresses. The direction of these stresses, however, has been studied even less, and much remains to be done with respect to studying them.
The critical meridians and parallels are significant for the water and air envelopes of the Earth as well as for the solid body of the planet. Their importance with respect to the water envelope has been recognized for a long time. The Pacific dislocations are obviously confined to the boundary between the continent and the ocean; they are displaced somewhat from the actual boundary, but they are strictly parallel to it. It is clear that these dislocations are closely related to those of the belt nearer the surface, as their parallelism indicates. In this case the role of the interaction of all the envelopes is perhaps even more obvious than for the latitudinal dislocations. This is not as clear for the Ural-African dis location and for the Mid-Atlantic Ridge, and they still require further study. However, their origin was apparently of the same type. It may be that the vagueness 'of the picture for these large dislocations is explained by the fact that they are of secondary importance, since they are only the gravimetric antipodes of the main dislocations playing an active role in this case.
In connection with the Pacific earthquake belt, corresponding to the regions of the Pacific deformations, I should like to note that they reach depths of more than 700 km, that is, they correspond to the deepest deformations (in particular, to deformations which are deeper than the deepest ones in the Tethys-Indian Ocean region). These earthquakes,
and the deep faults in the Earth's crust associated with them, have the same distribution as the smaller earthquakes do (their lines are parallel to one another). Both are oriented along critical meridians, and this is also noticeable in the Asian-Australian belt of the Pacific. This fact is noteworthy, since these same features characterize the symmetry of the body of the Earth, once we assume critical meridians as well as critical parallels. It should be emphasized that the meridional symmetry extends even further into the depths of the Earth than the latitudinal symmetry does. However, this still must be verified by more thorough investigations. For us here it is significant that, in the terrestrial gravitational field, the Earth's symmetry is expressed both in its gaseous and liquid outer envelopes and in the interior of the planet, down to the core itself.
We have mentioned that the theory of critical parallels proposed by Stovas makes no reference to the interaction of the envelopes or to the role of this interaction in carrying the effects of tectonic phenomena to great depths. The same applies to the theory of critical meridians of Katterfel'd and Spitaler, since they also ignore both the interaction of the envelopes and the interaction between oceanic tides and the continents.
The theory that the waters of the ocean exert a tidal effect on the continents was introduced by W. Thomson [Lord Kelvin] and formulated between 1879 and 1890 by G. H. Darwin. A good statement of the theory is given by Ball (1909). The basic idea of this theory was expressed correctly by Engels in "The Dialectics of Nature", when he stated that in the tides the Earth-Moon system transfers energy to individual regions on the Earth's surface. However, since the theory of critical parallels and meridians was still unknown in their time, the three above-mentioned investigators had no possibility of accurately specifying the regularities of distribution of the regions that Engels referred to. Now it is quite possible to do this, on the other hand, since a theory of critical parallels and meridians exists. The latter theory makes it possible to go even further, provided we complement it and the theory of a tidal effect of the ocean upon the continents with a clearly formulated conception of the interaction of the terrestrial envelopes which go to make up the body of the Earth, from the surface regions of the planet to very great depths. This is precisely what we are arriving at in the present article. By virtue of the interaction of the envelopes, then, spreading of the body of the planet originates.