13 



headed by Mr. Stewart, Civil Engineer of the Rotorna 

 Railway, who visited the district after the eruptions. 



In text book of Geology, Dr. Geikie, LL.D., F.R.S., 

 Director-General of the Geological Survey of Great Britain 

 and Ireland, says that : " The origin of earthquakes can only 

 " be conjectured. Sudden flushing into stream of water in 

 " the spheroidal state, the sudden condensation of steam, 

 " the explosion of a volcanic orifice, the falling in of the roof 

 " of a subterranean cavity, or the sudden drop of deep-seated 

 " rocks, subjected to prolonged and intense strain. In 

 " volcanic regions the frequent earthquakes which precede 

 " or accompany eruptions are doubtless traceable to explosions 

 •' of elastic vapours, and notably of steam. 



Professor John Milne, of the Imperial College of Tokio, 

 Japan, says that of the causes of earthquakes " The majority 

 " are due to explosive efforts at volcanic foci. The greater 

 " number of these explosions take place beneath the sea, and 

 " are probably due to the admission of water through fissures 

 " to the heated rocks beneath. Some earthquakes are 

 " produced by the sudden fracture of rocky strata, or the 

 " production of faults, this may be attributable to strains 

 " brought about by elevatory pressure. Lastly we have 

 " earthquakes due to the collapse of underground excavations." 



I think that there can be little doubt that volcanic action 

 forced up the ground at bottom of lake Tarawera, and that 

 the water poured on to the molten mass below, and the 

 enormous expansive body of steam from the water, let in by 

 degrees, kept on the violent ejecting force, and destruction of 

 adjacent land. 



