EFFECTS OF EARTHQUAKES. 



Morocco, Fez, and Mequinez were destroyed : all Europe expe- 

 rienced its effects at the same moment. From the different histo- 

 ries of earthquakes, many examples of this kind of propagation 

 might ne adduced, extending more or less widely. It may be even 

 concluded, from statements of facts, that the shock extends accord- 

 ing to a great circle, more or less inclined to the equator, and per- 

 haps over an entire hemisphere. 



4. Effects of Earthquakes. Earthquakes, when violent, not 

 only overturn entire cities, and the most solidly built edifices, but 

 they cause important modifications in the ground itself. Those of 

 Calabria, in 1783, furnish examples, which are the more important 

 because the facts were observed by the most distinguished men of 

 the times, such as Vicenzio, physician to the king of Naples, Gri- 

 maldi, Hamilton, Dolomieu, &c., and also by a commission ap- 

 pointed by the royal academy of Naples. All was overturned in 

 this unhappy country ; the course of rivers was interrupted and 

 changed ; houses were raised above the level of the country, while 

 others, frequently at no great distance, were sunk down more or 

 less ; edifices of great solidity were split from top to bottom ; cer- 

 tain parts were raised above others, and the foundations pushed up 

 out of the ground. Every where the surface of the earth partly 

 opened, often in long crevices, some of which were one hundred 

 and fifty yards in breadth ; some of these were isolated, sometimes 

 bifurcated frequently exhibiting other fissures perpendicular to 

 their direction (fig. 179) ; some were in form of rays diverging 

 from a centre, like a broken glass (Jig. 180). Some opened at the 



Fig. 179. Fig. 180. 



Crevices and fissures produced by earthquakes. 



moment of the shock, and immediately closed again, grinding be- 

 twixt their parietes the habitations they swallowed up ; others in- 

 variably remained gaping after the commotion, or, commenced by 

 A first snock, were widened by succeeding shocks. In both cases 

 it was sometimes observed that the borders of the split were on 

 the same plane, or showed a more or less projecting swelling up 



4. What are the effects of earthquakes ? What is the character of feu 

 eures produced by earthquakes ? 



