Hobbs — Features Formed at the Time of Earthquakes. 247 



water at such times results in : (1) local ejection of sand and 

 water (sand blows and mud cones), (2) draining through verti- 

 cal pipes of swamps or ponds ("funnels" and " craterlets "), 

 (3) in draining following upon an ejection of sand, mud and 

 water (pitted cones), or (4) squeezing out following the sudden 

 draining of the district. The best descriptions of such phe- 

 nomena have perhaps been given in connection with the earth- 

 quakes of Calabria, 1783;* New Madrid, 1811-12 ;f Iceland, 

 1896;;}: India, 1897 ;§ and Chemakha, Turkestan, 1902.| 



The mounds referred to in the above mentioned examples 

 generally consisted of sand mixed with small quantities of 

 various other substances (mica, lignite, etc.) generally foreign 

 to the surface layers of the soil, and it reached the surface 

 home by large volumes of water which left the material so 

 charged with water as to resemble a quicksand. During the 



Fig. 1. " Mud volcano " formed at Chemakha during the earthquake of 

 February 13, 1902. (After Weber.) 



Indian earthquake of 1897 material of this nature spread out 

 from many openings and blanketed large tracts of country 

 with quicksand. In other instances, as near ]STew Madrid, in 

 1811, the water and sand welled out throughout the length of 

 extended fissures and the arrangement of " sand-blows," like 

 the newly developed springs, appears to have been upon fissure 

 lines. During the Chemakha earthquake, and in some other 



*Lyell, Principles of Geology, vol. ii, pp. 113-144. 



fE. M. Shepard, The New Madrid Earthquake, Jour. Geol., vol. xiii, pp. 

 45-62, 1905. 



^Th. Thoroddsen, Das Erdbeben in Island im Jahre 1896, Pet. Mitth., 

 vol. xlvii, pp. 53-56, 1901. 



§R. D. Oldham, Report on the great earthquake of 12th June, 1897, Mem. 

 Geol. Snrv. India, vol. xxix, 1899. 



|| V. Weber, The earthquake of Chemakha of Jan. 31 (Feb. 13), 1902. 

 Mem. duComite Geol., N. S., No. 9, 1903 (in Russian). 



