226 THE ERUPTION OF VESUVIUS IN APRIL, 1906, 



From Ma}^ 25 to May 27 the Stromboliaii explosions increased in 

 intensity. Violent detonations were heard, and during the evening 

 of the 27th a fissure opened upon the northwest flank of the great 

 cone at an elevation of 1,245 meters, upon the site of the fumaroles 

 dating from the eruptions of August 20, 1903. Some hours later a 

 new fissure 023ened at 1,180 meters altitude, and for nearly a month 

 lava poured simultaneously from these two openings — an exceptional 

 fact for Vesuvius, because an orifice in activity generally ceases as 

 soon as another opens at a lower level. This outpouring of lava, 

 however, with accompanying explosive phenomena, continued with 

 maxima and minima of activity till April, 1906. 



The 3d of April, 1906, heavy detonations were heard; on the 4th, 

 at 5.30 a. m., earth movements were felt; then, while the fissure on 

 the northwest flank was still active, a new one opened upon the south 

 flank at an altitude of about 1,200 meters, and a small flow issued 

 which ceased at evening. The activity of the fissure on the northwest 

 flank had diminished, and ceased on the next day. 



During the morning of the 4th, and till midda}^, the crater was 

 the scene of explosions at first Strombolian and later Vulcanian. 

 These last destroyed the small interior cone and commenced the 

 destruction of the edges of the great cone. The dust formed by these 

 explosions was transported to Naples during the night. Another 

 opening formed on the south flank at an altitude of about 800 meters, 

 and the flow which issued therefrom traveled 2.5 kilometers with 

 a speed of 100 meters per hour. 



On April 6, about 8 a. in., when all the other openings were inactive, 

 a new one was formed on the southeast flank near Cognoli, at an 

 elevation of about 600 meters, from which a flow issued with a width 

 of 300 to 400 meters. A branch of this flow came to a point about 1 

 kilometer from Boscotrecase, traversing 3,800 meters in about thirty- 

 two hours. This opening, and another on the 7th, furnished much 

 of the lava that caused devastation in the plain. At the same time a 

 new opening farther east was formed at an elevation of about 750 

 meters, furnishing a flow which spread over older lava fields. The 

 flow issuing near Cognoli, already referred to, advanced through 

 inhabited regions, and on April 8, at 4 p. m., stopped within a feAv 

 meters of the cemetery of Torre Annunziata. All the inhabitants 

 of the countiy traversed by it, with the exception of three, were able 

 to save themselves. This great flow is 5.5 kilometers long and has 

 an average width of 300 meters. A minor flow followed later during 

 the night of April 10 from the same opening. 



The lava flows issued for the most part in the region south of the 

 cone from fissures opened successively lower on the flanks. 



The outpouring of lava formed only a part of the activity. Dur- 

 ing the evening of the 7th violent detonations were heard at Naples. 



