146 EARTHQUAKES, 



CHAPTER Vril. 



EFFECTS OF EARTHQUAKES OX LAND. 



1. Cracks and fissures — Materials discharged from fissures — Explanation 

 of fissure phenomena. 2. Disturbances in lakes, rivers, springs, 

 wells, fumaroles, &c. — Explanation of these latter phenomena. 

 3. Permanent displacement of ground — On coast lines — Level tracts 

 — Among mountains — Explanation of these movements. 



Cracks and fissures formed in the ground. — Almost 

 all large earthquakes have produced cracks in the ground. 

 The cracks which were found in the ground at Yokohama 

 (February 22, 1880) were about two or three inches wide, 

 and from twenty to forty yards in length. They could 

 be best seen as lines along a road running near the upper 

 edge of some cliffs which overlook the sea at that place. 

 The reason that cracks should have occurred in such a 

 position rather than in others was probably ovring to the 

 greater motion at such a place, due to the face of the cliff 

 being unsupported, and there being no resistance opposed 

 to its forward motion. It often happens that earthquake 

 cracks are many feet in width. At the Calabrian earth- 

 quake of 1783, one or two of the crevasses which were 

 formed were more than 100 feet in width and 200 feet in 

 depth. Their lengths varied from half a mile to a mile.^ 

 Besides these large cracks, many smaller ones of one or 

 two feet in breadth and of great length were formed. In 



• Lyell, Priiicijjles of Geology ^ vol. ii. chap. xxix. 



