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Mount Etna

Etna
Ash plume from 2002 eruption of Etna, photographed from the International Space Station
Elevation:	10,991 ft (3,350 m)
Latitude:	37° 44′ 3″ N
Longitude:	15° 0′ 16″ E
Location:	Sicily, Italy
Range:	—
Type:	Stratovolcano

Etna (or Aetna) is an active volcano on the east coast of Sicily (Italian Sicilia), close to Messina and Catania. It is 3,323 m (10,902 ft) high, about three times as high as Vesuvius, 140 km circumference at its base. On the safe part of its hills a famous wine is produced.

Etna is highly active, and currently the volcano has an eruption every few years. The constant monitoring, and the relative tranquillity of these eruptions, mean that there is little danger to human life. But sometimes, the lava streams burn down houses and gardens. On at least one occasion, a big lava stream has been diverted to a nearby empty valley to protect a village, though other villages have been lost.

Ancient eruptions

Only vague records of Etna's ancient eruptions survive. The Greek poet Pindar is the earliest writer who makes mention of its activity. He refers to it in his First Pythian Ode of about 470 BC, Strophe B, 1. The eruption discussed probably took place shortly before that date, since when there have been about sixty (?) recorded eruptions.

According to Carey's translation of Pindar:

From whose caverned depths aspire,

In purest folds upwreathing, tost

Fountains of approachless fire—

by day a flood of smouldering smoke

With sullen gleam the torrents pour

Virgil also describes the mountain very forcibly in the Aeneid, lib. iii. 570. Dryden's translation reads:—

The port capacious, and secure from wind,

Is to the foot of thund'ring Etna joined.

By turns a pitchy cloud she rolls on high:

By turns hot embers from her entrails fly,

And flakes of mounting flames, that lick the sky.

Oft from her bowels massy rocks are thrown,

And shivered by the force come piece-meal down.

Oft liquid lakes of burning sulphur flow,

Fed from the fiery springs that boil below."

Other Detail

Owing to Etna's great height, the lava seldom rises so far as to flow from the summit. It more frequently bursts forth from the flanks of the mountain; and in this manner there have been formed numerous smaller cones, of which several have craters of their own. Hence Etna is rather a group of volcanoes than a single cone; but all these subordinate volcanic hills cluster round the flanks of the great central summit. Some of these hills are covered with forests and rich vegetation, having enjoyed a lengthy rest from further lava flows. Others are still arid and bare, having been more recently formed. Owing to this peculiarity in its structure, Etna does not present the conical aspect which characterizes many other volcanoes. There are caverns on the sides of the mountain, which the Sicilians used for storing ice before the invention of refrigerators. Some of these caverns are large; one, called Fossa della Palomba measures 190 m in circumference at its entrance, and has a depth of about 24 m. This great cavity, however, forms merely the vestibule to a series of others, which are perfectly dark.

Another striking feature of Etna is the Val del Bove. It is a deep valley, presenting, when viewed from above, somewhat of the appearance of an amphitheatre. It stretches from near the summit down to the upper limit of the wooded region of the mountain, and has a remarkably desolate aspect, presenting a vast expanse of bare and rugged lava.

1669 Formation of Monti Rossi

Of the numerous eruptions of Etna, one of the most memorable was that of 1669, when an immense rent about 20 km long formed on the flank of the mountain above Nicolosi, about half way between Catania and the top of the great crater, from which a vast torrent of lava descended. After flowing for several miles, and destroying a part of Catania in its course, it entered the sea. This formed a small promontory, which has since proved very useful as a breakwater. As well as this lava flow, large quantities of ashes, cinders, stones, and other material were thrown up at the same time. This formed two conical hills, more than 100 m in height above the slope of the mountain from which they rose, and measuring nearly 3 km in circumference at their base. These hills were named Monti Rossi.

Eruption of 1852 — Whirlwinds — Lava torrents

An eruption in 1852 was of great violence. It began with hollow underground rumblings, and the ascent of dense columns of vapour, mingled with dust and ashes, high into the air. These were speedily whirled into enormous eddies by fierce whirlwinds. Two new mouths were formed on the side of the mountain, and these vomited forth immense streams of lava, which rushed with the vehemence of a torrent down the steep. The violence of the commotion increasing, the two mouths were, by the crumbling of the intervening rocks, blended into one, and then huge fragments of the broken rock were hurled to a great height, along with vast quantities of hot stones, cinders, and black sand. Increasing quantities of lava were now poured from the greatly enlarged opening, and these formed on the plains below a great river of liquid fire, nearly two miles in breadth, and between seven and eight feet in depth, which advanced at the rate of upwards of a hundred feet in an hour, carrying before it devastation and ruin. Its course being through a highly cultivated country, the damage it inflicted was immense. This eruption continued for several months, with only short intervals of rest. Etna was again active in 1865.

Cascades of lava

It has more than once happened, that the lava-streams of Etna, in their descent from the crater of eruption, have come to a precipitous wall of rock, over which they have plunged in a cascade similar to that formed by the lava of Vesuvius in 1855, but on a less magnificent scale, as respects the height of the fall. One of these occasions was during the eruption of 1771, and another during that of 1819.

Description of crater

The principal cone of Etna was ascended in 1834 by Messrs. Elie de Beaumont and Leopold von Buch. The former describes what they saw in the following terms:—"It was to us a moment of surprise difficult to describe, when we found ourselves unexpectedly on the margin—not, indeed, of the great crater—but of an almost circular gulf, nearly three hundred feet in diameter, which does not touch the great crater save at a small part of its circumference. We peered eagerly into this nearly cylindrical funnel; but vain was our search into the secret of its volcanic action. From the almost horizontal tops of the nearly vertical steeps, nothing can be descried but the upper cone. On trying to reckon those one below another, vision becomes gradually lost in the perfect darkness beneath. No sound issues from this darkness. There are only exhaled slightly sulphurous white vapours, chiefly steam. The dismal aspect of this black and silent gulf, in which our view was lost—its dark moist sides, along which crept, in a languid and monotonous manner, long flakes of vapour of a sombre gray—the great crater to which this narrow gulf is attached, with its confused heap of diverse substances, coloured yellow, gray, red, like the image of chaos—all presented around us an aspect quite funereal and sepulchral."

Empedocles

The French geologist, in having escaped from his visit to the crater with nothing worse than a fit of the vapours, came off better than Empedocles, the Sicilian philosopher, in the days of old: for, as the story goes, this inquisitive sage, being very anxious to have a peep into the crater, and venturing too near, toppled in altogether, and nothing more was seen of him, except one of his sandals, which was vomited up by the volcano—thus conveying to his friends an intimation of the manner of his death.

Enceladus

Some incredulous persons allege that this story has no better foundation than the fable of the poets, that the giant Enceladus, son of Titan and Terra, having offended Jupiter, the infuriated god first felled him with a thunderbolt, and then put Etna as a sort of extinguisher on the top of him—his restlessness underneath fully accounting for all the commotions of the mountain.

Craters of 1865

Soon after the eruption which took place towards the end of January 1865, the craters then opened were visited by M. Fouqué, a French geologist. At the time of his visit, 10th March, they were seven in number, and he thus describes their modes of action:—

"The three upper craters produced two or three times a minute, powerful detonations like thunderclaps. The lower craters, on the contrary, incessantly gave forth a succession of reports too rapid to be reckoned. These sounds, although unremitting, were clear and distinct, the one from the other. I can find no better comparison for them than the strokes of a hammer falling on an anvil. Had the ancients heard a similar noise, I can readily conceive whence arose the idea of their imagining a forge in the centre of Etna, with the Cyclops for workmen."