THE CAUSE OF EARTHQUAKES, ESPECIALLY THOSK 
OF THE EASTERN UNITED STATES ' 
By WILLIAM HERBERT HOBBS 
CONTENTS 
Part I. GENERAL 
Early earthquake theory: 
Scriptural doctrine. 
Aristotelian view. 
Humboldt’s idea of safety valves. 
Modern dress of Aristotle’s doctrine, Mallet, 1862. 
The Unique fault theory: 
Japanese earthquake of 1891, Kot6, 1893. 
Hindustan earthquake of 1897, Oldham, 1899. 
The Theory of mountain growth, De Montessus, 1906: 
Two earthquake girdles. 
Mesozoic geosynclines. 
Adjustments within a fault mosaic as corollary to mountain growth: 
Tarr and Martin, 1906. 
Hobbs, 1907. 
W. D. Johnson, 1907. 
Seismic world map, 1915. 
Magma pocket below and vent above earth wrinkles. 
Omori’s law of geographical succession of earthquakes within girdles. 
Harthquake prediction. 
Elastic rebound theory of Reid, 1910: 
Theory stated. 
Its inadequacy. 
Sekiya’s wires. 
General statement of probable cause of earthquake: 
Proximate cause. 
Ultimate cause. 
Part II. HARTHQUAKES OF THE HASTERN UNITED STATES 
The region a relatively stable one: 
Historical earthquakes of the region. 
Epeirogenice earthquakes of De Montessus, 1924. 
Hpeirogenic adjustments within Great Lakes area. 
Postglacial faults. 
Conclusion. 
1 Reprinted by permission from papers of the Michigan Academy of Science, Arts, and 
Letters, Vol. V, 1925. 
257 
