388 Transactions. — Geology. 



Art. XLIII. — The Volcanic Outburst at Te Mari, Tongariro, 

 in Nov ember, 1892. 



By H. Hill, F.G.S. 



[Eead before the Haivke's Bay Philosophical Institute, 12th June, 



1S98.] 



I THINK it ought to be placed upon record that a very important 

 eruption took place on the Tongariro Mountain about the 

 middle of November last year. At the northern end of the 

 mountain, and outside what is properly the old Tongariro 

 crater, are two centres of activity. One is known as Kehetahi, 

 situated on the north-west side of the mountain, at a height of 

 4,900ft. ; the other is Te Mari, situated at the north-east end, 

 at a height of 5,600ft., and immediately above Lake Eoto- 

 aira. Few people have ever visited the latter spot, owing to 

 the difficulties of reaching it ; besides, its existence only dates 

 back a few years. In a paper read by me two years ago on 

 Euapehu and Tongariro,''' I pointed out that of all places in the 

 volcanic district Te Mari is the spot for vulcanologists to visit, as 

 it was here that volcanoes in embryo could be seen and studied. 

 Ever since the time of the Tarawera eruption there has been 

 a perceptible growth of volcanic activity in the group of volcanic 

 cones forming the Tongariro Mountain system. Ngauruhoe 

 and Euapehu have by various explosions shown their growing 

 activity, and the mud-pools, solfataras, and explosion-vents at 

 Kehetahi have not only increased in intensity, but the area of 

 activity has been slowly widening, and new places— like new 

 wounds about an old one — are slowly breaking out near to the 

 main centre of activity. Te Mari, when visited by me in March, 

 1890, consisted of three shafts of unknown depth, each having 

 a crater like an inverted cone, whose centre was the mouth of 

 the shaft. A gyratory force from below had evidently shaped 

 the craters in this way as a prelude to the flowing of lava. 

 Sulphur, or what seemed to be sulphur, was deposited here 

 and there in the crater, and steam was rising in fair quantity 

 from each shaft. The appearances betokened much activity 

 below, and the loose sands and debris around showed that 

 explosions had taken place at no distant date. To the north- 

 west of the shafts, and separated only by a small ridge of lava, 

 is an immense crater of great depth. The walls of this crater 

 are finely banded, showing lava-streams of slightly different 

 characters, and illustrate the way in which the lava must have 



* Trans. N.Z. lust., vol. xxiv., p. GOT. 



