DISTRIBUTION IN SPACE AND TIME. 231 



lising and falling of these lips throw off transverse waves. 

 Eossi adduces observations w^hich appear to meet with 

 explanation on such suppositions. 



Suess, who has written upon the earthquakes of lower 

 Austria, shows how the majority of the disturbances have 

 had their origin along certain lines which form a break in 

 the continuity of the Alps. One line runs north-east from 

 Bruck towards Vienna. Kear Wiener Neustadt, where the 

 greatest number and heaviest shocks have occurred, this 

 line is met by a north-north-west line crossing the Danube 

 and following the valley of the river Kamp.^ Hoeffer has 

 drawn similar lines from the head of the Adriatic, one set 

 running north-north-east to intersect near Litschau, and 

 the other north-north-west to intersect near Frankfort in 

 the valley of the Ehine.^ 



Examiples of distribution, — A curious example of the 

 distribution of seismic movement is that of the earthquake 

 of March 12, 1873, worked out by Professor P. A. Serpieri. 

 This earthquake appears to have been simultaneously felt 

 on the Dalmatian coast and in central Italy, in a region 

 lying north-east from Eome and south-east from Florence. 

 In both of these areas the motion was from south-east to 

 north-west. The shock then radiated from the central 

 Italian regions, so that at places on the western shore 

 of the Adriatic it was felt after it had been felt on the 

 Dalmatian coast. 



Many explanations might be offered for this peculiar 

 distribution of seismic activity. Possibly the shock 

 originated at a great depth beneath the bed of the 

 southern part of the Adriatic, and by following existing 

 lines of weakness simultaneously reached the surface of the 

 earth in central Italy and Dalmatia. 



* E. Suess, Die Erdhelen NiederbsterrncJies. 



* H. Hoeffer, Die Erdhehen KdrnterCs. 



