216 



ANNUAL EEPOET SMITHSONIAN INSTITUTION, 1915. 



If an attempt is made to trace the isoseismic curves of the iDrincipal 

 shock, it will be seen that the area most affected (fig. 1) contains 

 alluvial strata of the dried-up Lake of Fucino, and embraces a zone 

 to a high degree sedimentary and of Karstic origin. This precludes 

 any volcanic cause for the earthquake; it is likely, on the contrary, 

 that it was due to a sudden modification of the deep stratifications of 

 the earth's crust. The region of Marsica which was the epicenter of 



Fig. 2.— Distribution of the Italian earthquakes along a fixed line, according to Prof. Omori. 



the earthquake, although having a seismic character, had not until 

 that time been the scene of any great catastrophes. 



The present phenomenon, adds Dr. Martinelli, was in a way pre- 

 dicted by science. In fact. Prof. Omori, in a study of the great Ital- 

 ian earthquakes from 1G38 to 1908, in Sicily, Calabria, and in central 

 Italy, came to the conclusion by an examination of the stricken area 

 that earthquakes follow a determined line and that an area in which 

 an earthquake takes place never coincides with that of a previous 

 quake. In a chart of southern Italy (fig. 2) traced by the learned 

 Japanese seismologist it will be noticed that the destructive area of 



