246 W. H. HOBBS ORIGIN OF OCEAN BASlNS 



quake of December 7, 1885, where it lay in only 300 feet of water and 

 only 1 mile off the Zante shore. With a sea telescope the smooth lime- 

 stone bottom could be seen, with the line of the former position of the 

 cable marked on it; but this was now 2 feet away, and the cable was 

 found actually lifted off the bottom. Exactly Avhere the cable had lain 

 at one point there was a deep hole in the limestone, with radiating frac- 

 tures presenting the "appearance a large pane of glass has when frac- 

 tured."* 



At the time of the great Ligurian earthquake of February 23, 1887, 

 no faults appeared on the land, but several vessels a few miles off the 

 coast received shocks so severe that it was at first thought they had struck 

 bottom. During the following days a large number of deep-sea fishes, 

 including Alepocephalus rostratus, were found dead in the shallow water 

 along the Eiviera or were stranded on the beach, especially in the neigh- 

 borhood of Mce.f The earthquake at Kingston, Jamaica, January 14, 

 1907, was acocmpanied by a sinking of the harbor bottom by as much as 

 27 feet, and step faults upon the neighboring shore recorded an addi- 

 tional drop of 24 feet, making 53 feet as the total depression of the har- 

 bor bottom. J 



CoNTEASx OP Movements of crustal Blocks within the conti- 

 nental AND UNDER-SEA AREAS 



The data above given not only reveal the possibilities of investigation 

 along these lines, but, as already stated, they seem clearly to show that 

 the changes in the configuration of the sea bottom by seaquakes are on a 

 much grander scale than those with which we are now becoming familiar 

 upon the land.§ To produce the seismic tsunamis such as those which in- 

 undate the eastern shore of Japan, and still more those larger waves 

 which are registered by tidal gauges over the entire globe, it is necessary 



* This description recalls the fractures radiating from a point, so familiar from the 

 description and cut of the fissures found at Gerocarne during the Calabrian earthquake 

 of 1783. 



t Charles Davison : A study of recent earthqualies. London, 1905, pp. 162-163. 



J Charles W. Brown : The .Jamaica earthquake. Pop. Sci. Month., vol. 70, 1907, p. 401. 



§ The largest displacements of earth blocks yet demonstrated on the land were in 

 connection with the Iceland earthquake of February, 1875, when the depression of 

 Sveinagja sank between faults 47 to 65 feet (P. de Montessus de Ballore, Les tremble- 

 ments de terre, Paris, 1906, p. 110), and in Alaska, at the time of the earthquake of 

 September, 1899, when the shores of Yakutat bay rose in places 47 feet above the sea- 

 level (Tarr and Martin, Bull. Geol. Soc. Am., vol. 17, 1906, pp. 29-64, pis. 12-23). Sur- 

 face faults have been produced of 33 feet throw in connection with the Assam (Indian) 

 earthquake of 1897 (Oldham, Mem. Geol. Surv. India, vol. 29, 1899, pp. xxx and 379, 

 44 pis.). Displacements of the same order of magnitude occurred in connection with 

 the earthquakes of India in 1818 (20 feet 6 inches), Sonora in 1872 (20 feet), and 

 Owens valley in 1887 (20 feet). 



