106 



EARTHQUAKES. 



fig. 18, then c d will represent the direction in which the 

 shock emerged, which is at an angle of 23°*20' to the 

 horizon. It might be argued that the direction of these 

 fractures was due to the direction in which surface undu- 

 lations had travelled, or to the relative strengths and 



Fig. 19.— The Cathedral, Paterno (Mallet). Neapolitan Earth- 

 quake of 1857. 



proportions of different portions of the building. The 

 directions of cracks in a building are undoubtedly due to a 

 complexity of causes, but for buildings situated in the 

 region of shock the impulsive effect of the shock is pro- 



