BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 28, pp. 249-278, PLS. 6-9 MARCH 31, 1917 



PEESISTENCE OF VENTS AT STEOMBOLI AND ITS BEARING 

 ON VOLCANIC MECHANISM - 



BY HENRY S. WASHI>sTGTOX 



{Presented before the Society December 29, 1916) 



CONTENTS 



Page 



Introduction • • 249 



Stromboli 251 



Kilauea 269 



Etna and Vesuvius 270 



General discussion 271 



Ij^troduction 



A visit to Stromboli^ in August^ 1914^ brought to my attention a feature 

 of this volcano which has been overlooked generally by writers on vol- 

 canism. This is the apparent persistence in location of several of the 

 active vents in the crater floor or ^^terrace" for a period of at least about 

 a century and a half. Further consideration of this and other features 

 of the Stromboli vents, as well as of similar features at other volcanoes, 

 have led me to some generalizations in regard to the mechanism of vol- 

 canic action. 



Briefly put, there are at Stromboli certainly three, and probably six, 

 vents which have persisted in location for a very considerable length of 

 time. These vents are all of small diameter, contiguous to each other 

 within a small area, and one or more of them have been more or less 

 continuously active. As will be shown, they are presumably the mouths 

 of narrow, essentially vertical, disconnected conduits, which have been 

 bored through solid strata close to the edge of a high and steep scarp. 

 The same peculiarity of situation is found in certain parasitic vents at 

 Kilauea and on the edge of the Val del Bove scarp at Etna. Some vents 

 at Kilauea and at Etna and Vesuvius likewise show the features of per- 



* Manuscript received bj- the Secretary of the Society November 15, 1916. 



1 This name is accented on the first syllable, not on the second, as is commonly done. 



(249) 



