289 
(790 m.), while that of the pass between Falling Mountain and 
Trident Volcano is 2800 feet (850 M.) high. 
The course which is taken in my opinion by the hot lahar is 
drawn on the annexed diagram (fig. 2) by a dashed line. Coming 
from Katmai crater with great rapidity the lahar descended towards 
the west, bifurcated the first time near Broken Hill, whereby the 
main part flowed westwards and a smaller part towards the south- 
west between Broken Hill and Trident Voleano. A second bifurcation 
took place near Falling Mt.; one part flowing in a westerly direction 
and after turning to the north joining the main flow, whereas the 
other part flowed to the south and southwest over Katmai-pass and 
descended as far as Mageik Creek toa level of + 1400 feet (425 m.). 
This has been derived from Griccs’ map. He will be able to say 
wether if it agrees with his detailed observations. 
What still calls for an explanation is the fact that the mud flow 
has not been found between the western crater rim (+ 6000 feet = 
1820 m.) and the contour-line of 3000 feet (910 m.). A similar 
phenomenon, though less striking') is also observed at the Klut. It 
is due to the fact that the lahar erodes in the shorter and steeper 
upper part of his course and can lay down deposits only within the 
much longer and more level lower part. The name Klut signifies: 
sweeper; at each eruption he entirely cleans away great parts of 
his slopes and further on sweeps away cultivations and villages. 
In connection with the above mentioned phenomena I should like 
to propose the following nomenclature for mud flows: 
I. Specific volcanic mud flows: 
1. By an eruption through a crater lake: Type 
lahar (hot lahar) Klut (Java) 
(hot mud flow) 
2. By melting of an ice-cap by an eruption: jökulhlaup Iceland 
II. Not specifie vuleanie mud flows : 
3. By heavy rains on loose material: Murgang (cold lahar) 
(cold mud flow) 
In the above I have tried to prove that the Katmai eruption of 
1912 was an enlarged edition of the Klut eruptions which have 
been so often observed (fig. 3), and that the hot mud flow of the 
Valley of Ten Thousand Smokes was a hot lahar. 
1, The narrow Durga-canyon brakes the lahar which therefore partially 
remains behind. 
