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Earthquakes in the Light of the New Seismology
Earthquakes in the Light of the New Seismology Author:Clarence Edward Dutton Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: - CHAPTER II CAUSES OF EARTHQUAKES The Three Views—The Dislocation Theory—The Volcanic Theory—Views of Humboldt and Boussingault—The Tidal Theory—Perrey... more »'s Inquiries and Laws—The Statistical Method of Investigation—Milne's Catalogue in Japan—De Montessus de Ballore—Sources of Earth Stresses—The Contractional Hypothesis—The Ideas of Babbage and Herschel—Iso- static Equilibrium—Prof. George Darwin's Discussion of Stress-differences and their Distribution—The Relative Magnitudes THE originating or ultimate causes of earthquakes have been the subjects of controversy for more than a century. ,lt would be curious and amusing, rather than useful, to go back into the eighteenth century to exhume buried and forgotten hypotheses put forth to explain these phenomena. They seem to indicate the fanciful childhood of the science which endeavours to deal with problems of earth physics. It will be more profitable to limit ourselves to those explanations which, though they may be more or less erroneous, are neither childish nor absurd. During the first half of the nineteenth century these might be divided into three groups: 1st, those which attributed earthquakes to sudden downthrows or collapses of the ground; 2nd, those which attributed them to volcanic action; 3rd, those which attributed them to theaction of a liquid interior of the earth upon an external rocky crust under the disturbing influence of tidal forces. As none of these theories have been fully disposed of, and as all of them still have more or less vitality at the present time, we may in a preliminary way briefly advert to them. The downthrow, or downfall, or Einsturzthcorie has had f for its advocates J. J. Scheuchzer, in his day an eminent Swiss geologist'; Boussingault," a far more illustrious naturalist; Albert ...« less