EAR THQ UAKES. 2 $ I 



the case of the earthquake of Calabria in 1783. This 

 celebrated earthquake began in February, 1783, and 

 lasted until the end of 1786. The first shock threw 

 down, 4 in two minutes, nearly every house in all the 

 cities, towns, and villages, from the western flanks of 

 the Apennines in Calabria Ultra to Messina in Sicily, 

 and convulsed the whole country.' The second took 

 place seven weeks later, and was scarcely less violent. 

 Sir Charles Lyell mentions that 'the great granite 

 chain which passes through Calabria from north to south 

 and attains the height of many thousand feet, was 

 shaken but slightly by the first shock, but rudely by 

 those which followed.' 



The manner in which a large extent of country was 

 permanently affected by this earthquake is very well 

 worth noticing, as affording an excellent illustration 

 of the mode in which earth-waves travel. 



The Apennines are formed for the most part of 

 massive and hard granite, with steep inclines, upon the 

 base of which lie those strata of sand and clay which 

 form the Calabrian plains. These plains are usually 

 level, but are intersected in places by narrow valleys 

 and ravines whose sides are almost vertical. The effect 

 of the earthquake was to shake down those parts of the 

 Calabrian plains which border on the granite backbone 

 forming the Apennine range. The soil ' slid over the 

 solid and inclined nucleus, and descended somewhat 

 lower,' says Lyell, ' leaving almost uninterruptedly from 

 St. George to beyond St. Christina a distance of from 

 nine to ten miles a chasm between the solid granite 



