260 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1926 
The great earthquake of 1891 in the Neo Valley of Japan was the 
first to supply striking photographs of changes produced at such 
times in the surface of the earth, and these photographs came quite 
generally into the hands of scientists.2, Though they produced a pro- 
found impression they did not immediately discredit the centrum 
theory. The pictures showed that for many miles across the country 
a fracture of the ground appeared at the time of the earthquake, 
and that along this fracture the land upon one side had been raised 
relatively to that upon the other by as much as 18 feet at one place; 
while at other places though neither side had been raised or lowered 
in reference to the other, the two sides of the displacement had 
slipped past each other in opposite directions along the surface of 
the ground a distance of the same order of magnitude as that shown 
by the vertical displacement. It did not admit of doubt that these 
scissorlike movements on the ground, whether up or down or along 
the surface, had been sudden and violent and had, moreover, been 
connected with the jolting movements to which the term earthquake 
had been applied.* 
Hindustan earthquake of 1897, Oldham, 1899.—Six years later 
occurred the great Assam (Hindustan) earthquake which was also 
carefully studied. In this case though a small part only of the 
affected area was examined, there were found no less than three 
fracture displaeements (faults), and the maximum vertical displace- 
ment measured was about 35 feet. The likelihood is that a number 
of other faults were produced at the surface, though the localities 
were not visited by any representatives of the scientific personnel 
of the Indian Survey. Stress was, however, laid upon one plane 
only of fracture and displacement, and this was believed by Oldham 
to be a thrust on a plane of low angle to the horizon. 
THE THEORY OF MOUNTAIN GROWTH, DE MONTESSUS, 1906 
Two earthquake girdles——The late Count de Montessus de Ballore 
published in 1906 the results of an exhaustive study of the distribu- 
tion of earthquakes, as a result of which he reached this conclusion: 
The earth’s crust quakes almost in equal amounts and almost entirely along 
two straight zones which lie along two great circles (in the geometric sense) 
which make an angle with each other of about 67°—the Mediterranean or 
Alps-Caucasus-Himalaya circle (53.54 per cent of the earthquakes), and the 
2John Milne and W. K. Burton, professors in the Imperial University, “The great 
earthquake in Japan, 1891,” 30 photogravures, plates, and map with descriptions. Lane, 
Crawford & Co., Yokohama (no date). 
8B. Koté, ‘On the cause of the great earthquake in central Japan, 1891,’’ Journ. 
College Sci. Imp. Univ., Tokyo, vol. 5, 1893, pp. 295-355, pls. 28-35. 
*R. D. Oldham, ‘‘ Report on the great earthquake of 12th June, 1897,’ Mem. Geol. 
Surv. India, Calcutta, vol. 29, 1899, pp. 379, pls. 42, maps. 
