CALABRIAN EARTHQUAKE 72 1 



map of the earthquake of 1905, and these lines are prominent lineaments and 

 in many cases known faults. 



Third. The communes of highest seismicity lie at the intersections of seis- 

 motectonic lines. 



Fourth. Within an area common to the destructive territory of three catas- 

 trophic earthquakes (1659, 1783, and 1905) whose "centrums" were widely 

 separated, the distribution of damage was essentially the same — the included 

 communes maintained the same relative position as regards the damage sus- 

 tained. 



From these facts it appears that earthquakes have no centrum as this term 

 is ordinarily understood, but in so far as so-called epicenters are positions of 

 greatest intensity of shocks, they are numerous and habitual and correspond 

 to the intersection of fissure planes projected upon the surface. It also ap- 

 pears that shocks of earthquakes below X in the Rossi-Forel Scale are im- 

 potent to wreck well constructed buildings at distances of a mile or more 

 from the fissure planes. 



When the investigation was about completed there appeared the epoch- 

 making work of the Count de Montessus de Ballore* upon the distribution of 

 seismicity and its relation to topography and geology — "seismic geography." 

 Upon a large scale adapted to the methods used, Major de Montessus has located 

 the habitual epicenters for all earthquake provinces of the globe. Applying 

 the methods discovered in Calabria to the maps of de Montessus, it is found 

 that almost throughout the habitual epicenters are the intersections of im- 

 portant lineaments. 



A special study has been made of the eastern United States and Canada on 

 the basis of data supplied by de Montessus, and it is found that the habitual 

 epicenters of this large region are the intersections of the grand lineaments as 

 they have already been plotted* with others brought to light by a considera- 

 tion of the steep walls of the continental shelf. The full reports are to appear 

 as heft 2 of volume viii of the Beitrage zur Geophysik, the journal of the 

 International Seismological Association. 



QUAD IX FORMATION OF GRANADA, SPAIN 

 BY WILLIAM H. HOBBS 



This paper is printed as pages 285-294 of this volume. 



VOLCANIC CRATERS IN THE SOUTHWEST 

 BY CHARLES K. KEYES 



Several years ago Mr G. K. Gilbert aroused considerable interest among 

 scientists by the announcement that he had visited in Arizona a large crater, 

 depressed below the level of the plains, about which large numbers of meteoric 

 masses had been found. The main hypothesis considered regarding the origin 

 of the depression was that of a large meteorite striking the earth at this 

 point. The phenomenon is thus described:* 



* Les tremblements de terre, Paris, 1906. 



* Lineaments of the Atlantic border region. Bull. Geol. Soc. Am., vol. 15, 1904, pp. 

 483-50G, pis. 45-47. 



* Presidential address before Geological Society of Washington, 1896. 



