THE INTERNATIONAL SCIENTIFIC SERIES VOLUME LV THE INTERNATIONAL SCIENTIFIC SERIES EARTHQUAKES AND OTHER EARTH MOVEMENTS BY JOHN MILNE PROFESSOR OF MINING AND GEOLOGY IN THE IMPERIAL COLLEGE OF ENGINEERING, TOKIO, JAPAN _WITH THIRTY-EIGHT FIGURES_ NEW YORK D. APPLETON AND COMPANY 1, 3, AND 5 BOND STREET 1886 PREFACE. • • • • • In the following pages it has been my object to give a systematic account of various Earth Movements. These comprise _Earthquakes_, or the sudden violent movements of the ground; _Earth Tremors_, or minute movements which escape our attention by the smallness of their amplitude; _Earth Pulsations_, or movements which are overlooked on account of the length of their period; and lastly, _Earth Oscillations_, or movements of long period and large amplitude which attract so much attention from their geological importance. It is difficult to separate these Earth Movements from each other, because they are phenomena which only differ in degree, and which are intimately associated in their occurrence and in their origin. • • • • • Because Earthquakes are phenomena which have attracted a universal attention since the earliest times, and about them so many observations have been made, they are treated of at considerable length. As very much of what might be said about the other Earth Movements is common to what is said about Earthquakes, it has been possible to make the description of these phenomena comparatively short. The scheme which has been adopted will be understood from the following table:— I. EARTHQUAKES. 1. Introduction. 2. Seismometry. {(_a_) Theoretically. 3. Earthquake Motion. {(_b_) As deduced from experiments. {(_c_) As deduced from actual Earthquakes. 4. Earthquake Effects. {(_a_) On land. {(_b_) In the ocean. 5. Determination of Earthquake origins. {(_a_) In space. 6. Distribution of Earthquakes. {(_b_) In time (geological time, { historical time, annual, { seasonal, diurnal, &c.) 7. Cause of Earthquakes. 8. Earthquake prediction and warning. II. EARTH TREMORS. III. EARTH PULSATIONS.