ApkIL 20, 1905] 



NA TURE 



59: 



RECENT CHANGES IN THE CRATER OF 

 STROMBOLL' 

 CTROMBOLI is the most easterly and northerly of the 

 ^ Lipari Islands. It is situated north of Sicily, close 

 to the track of steamers plying between Naples and the 

 Straits of Messina, and is thus an object familiar to 



.^ 



passengers to or from Egypt or the East, though com- 

 paratively few have landed on its shores. Its almost con- 

 stant eruptions have gained it the name of the lighthouse 

 of the Mediterranean. It is almost circular, as its old 

 name Strongyle indicates, and rises as an irregular cone 

 out of deep water. On the north- 

 west side are the crater, and the 

 Sciara or steep slope down which ihe 

 ejecta roll into the sea. 



The summit of the mountain, 

 which is about 3000 feet high, con- 

 sists of a crescentic ridge, the Serra 

 di Vancori, open towards the north. 

 It forms part of an old crater ring, 

 and thus presents points of similarity 

 to Somma. Inside the crescentic 

 ridge, and in places joined to it by 

 irregular crests of rock, but mainly 

 separated from it by a valley, " A 

 Fossieiedda," similar to the Atrio del 

 Cavallo of Vesuvius, is .another cres- 

 centric ridge, connected with the two 

 extremities of which, and immedi- 

 ately overlooking the sides of the 

 crater, are two conspicuous pointed 

 rocks, the Torrelle, which partly 

 obstruct the view of the crater when 

 viewed from the cliffs overlooking 

 the Sciara on its north-east and 

 south-west respectively. These 



Torrelle, being practically unaltered 

 by ordinary eruptions, present good 

 points of comparison for estimating 

 the changes that take place, and one 

 or other of them is included in most 

 of the photographs. Between the 

 two Torrelle, in the midst of a sort 



of amphitheatre formed by them and the crescentic ridge 

 last mentioned, are the crater and its appurtenances, the 

 " Apparato Eruttivo " of Italian observers. This amphi- 



1 Abridged from a paper by Dr. Tempest Anderson in the Ccograplticnl 

 Joitritat for February. 



NO. 185 1, VOL. 71] 



theatre is open to the north-west, and from its open side 

 beyond the craters the steep slope of the Sciara extends 

 down into the sea. This slope is bounded on each side by 

 two steep cliffs, Filo di Sciara and Filo di Bar.'iona, which 

 are formed, like the Sciara itself, of lava-streams, agglo- 

 merates, and dykes ; in fact, of almost every kind of com- 

 pact volcanic material, chiefly of basic composition. 



This .Sciara, as is well known, is 

 one of the most peculiar features of 

 this volcano. It extends at an angle 

 of about 35°, which is the " angle 

 of repose " for the kind of material 

 of which it is composed, down into 

 the deep water of the Mediterranean ; 

 and though the volcano has certainly 

 been in almost constant eruption 

 during the whole of the historic 

 period, and probably much longer, it 

 has never been able to build up a 

 talus sufficient to rise to the level of 

 the sea, much less to that of the lip 

 of the crater, about which, accord- 

 ing to the analogy of other vol- 

 canoes, it might have been expected 

 to have built up a cone on this side 

 ^ comparable to the portion on the 



south described above. Fig. i, from 

 a phrtograph ' taken by the author 

 in 1888 from the ridge overlooking 

 the north-east side of the Sciara, 

 and consequently looking south-west, 

 shows the Sciara extending down to 

 the right of the picture with the File 

 de Barcuna behind it. The pointed 

 ■■ rock to the left of the picture is the 



eastern Torrella, with a gap to the 

 left of it through which the ejecta 

 are thrown during the larger erup- 

 tions, and roll on to the steep slopes 

 in front and down the Sciara into the sea. The western 

 Torrella is just visible in the distance beyond the eastern 

 Torrella. The crater situated between the two was in 

 1888 a large pit obviously formed by severe explosions. 

 It contained two small secondary cones. One, towards its 



western part, and close to the edge of the Sciara, was 

 that from which the explosive eruptions took place several 

 times an hour; the other, towards the eastern part, emitted 

 only smoke. 



1 From " Volcanic Studies," by Temrest Anderson, [late .•<x;. 



