Hydrogeothermal theory of earthquakes ? Basis of prediction, warning systems, and counteractions

Abstract

It is presently generally recognized that under certain conditions the creation of reservoirs, injection of water into deep wells, and the pumping out of oil and gas are the cause of a sharp increase of seismic activity.Such technogenic ("induced," "stimulated") earthquakes differ in no way from "ordinary" ones. The mechanism of this phenomenon, just as the focal mechanism of an "ordinary" earthquake, is not clear.In the given case we are dealing with a paradoxical situation. On the one hand, it would seem, technogenic earthquakes only add vagueness to the already unclear problem of the focal mechanism.But, on the other hand, the very fact of the effect of technical factors on the focal mechanism (which not long ago was completely denied) and examples of their various combinations make it possible to pose more clearly the question about studying the focal mechanism in the general case. In this regard we can quote the statement of the prominent French seismologist Rothe:"... The exact mechanism of strong artificial earthquakes is not understood, although it is clear that, just as in the case of natural earthquakes, in this case the energy stored in a limited volume of rocks is released through weakened zones. Whereas the origin of natural earthquakes is unknown, the relation of artificial earthquakes to the weight of the water load is obvious."It can be hoped that a study of artificial earthquakes will help to solve the problem of earthquake prediction in the general case." But if we can affect seismicity toward its increase, then on the basis of general principles we can pose the question about developing technical measures not allowing its increase during construction of dams and in other similar situations.The next, completely logical step will be the development of measures to reduce seismicity under ordinary conditions in earthquake-prone regions.The primary and most vital task will be, of course, the organization of an automatic earthquake warning service on the basis of a system of instruments (measuring the water level, temperature, etc.) installed in the region of a potential focus. Attention is called to the fact that such an automatic warning service basically differs from the presently existing practice of earthquake prediction. However, for this purpose it is necessary in principle to change the approach to a study of this problem.For all the complexity of the question about the probability of earthquakes, a passive approach developed in a study of this problem, dooming science and practice just to the collection of information about earthquakes occurring with the timid hope in the distant future of establishing some sort of earthquake prediction systems. As regards an automatic warning system and especially an earthquake counteraction system, such an undertaking is presently practically completely precluded by this approach.Unconditionally, equipping of a large number of seismographic stations with computers will increase the quantity of observation data and simplify their processing, but it will not...