1909.] OUTLOOK OF SEISMIC GEOLOGY. 269 



phenomena are simultaneously in progress. A suboceanic trough may sud- 

 denly subside, whilst its bounding ridge may be suddenly increased in height, 

 and the concertina-like closing of the trough may account for the sea-waves. 



Dutton, in 1904,^^ included in his classification tectonic earth- 

 quakes, and by supplying data concerning the earthquake of Sonora 

 in 1887 contributed an additional example of uplift en bloc of a 

 mountain mass accompanied by a great earthquake. Of this range, 

 the Sierra Teras, he says : 



In other words, the range seemed to have been uplifted several feet 

 between faults on either flank. 



Yet the implication in the context is that these observations are 

 hardly decisive, and in a paper read before the National Academy 

 of Sciences in 1906^- it is made clear that Dutton at this time still 

 adhered strongly to a modified centrum view to which he had con- 

 tributed in 1889 in his report upon the Charleston earthquake of 

 1886. 



The Dutch geologist, Verbeek, in 1905 published a catalogue of 

 the earthquakes of the island of Ambon in the East Indian Archi- 

 pelago, together with a full account of the heavy earthquake which 

 caused much damage upon the island on January 6, 1898.^^ His 

 study of the distribution of the damage resulting from the latter 

 quake brought out the fact that the shocks were largely limited to 

 narrow zones on either side of a main fault running in a north and 

 south direction across the island, and to similar zones about three 

 additional faults which cross the first nearly at right angles, the 

 stronger shocks belonging with the first mentioned displacement. 

 Of this north and south zone he says: 



The terrane most disturbed, which one designates " the pleistoseismic 

 area" does not here have the form of a circle or of an ellipse, as in the case 

 of so many earthquakes, but that of a long band relatively straight, which 

 shows clearly that we have here to do with a tectonic quake; now since we 

 have shown above in the description of the geology that there is at the 

 south of Ambon a fault which is prolonged to the north through Ambon 

 and southward ... to the southern coast, it is altogether natural to 

 attribute the earthquake to a new dislocation along this cleft or fault of the 



" " Earthquakes in the Light of the New Seismology," 1904, p. 55. 

 " " Volcanoes and Radio Activity," Englewood, N. J., 1906, p. 5. 

 " R. D. M. Verbeek, " Description Geologique de I'isle d' Ambon," Batavia, 

 1905, pp. 300-323- 



