North rim of the largest and most impressive of the 1809 craters on Etna's Northeast Rift, late June 1999. This crater gives interesting insights into the dynamics of its formation, because in its walls is exposed the initial feeder dike that led to the opening of an eruptive fissure at the beginning of the eruption; the large craters visible today formed at a later stage during the same eruption. Person on left crater rim gives an approximate scale

Mamma Etna's countless children
1809 craters
NE flank, 15.011839° E, 37.786377° N
Summit elevation: ~2390 m (SW crater rim)

Among the most spectacular of the numerous craters on the Northeast Rift are two huge pits with low pyroclastic rims that were formed during a brief but powerful eruption in 1809. They lie at a maximum altitude of about 2390 m and form, together with two smaller craters further downrift, the central segment of an eruptive fissure system that extended from near the summit down to about 1350 m elevation, over a total length of 10 km. Strong explosive activity took place in the central section of the fissure system, leading to the formation of the craters described on this page.
The 1809 craters, and in particular the largest and uppermost of them, provide interesting insights into the dynamics of the opening of an eruptive fissure and its later evolution into distinct craters. The crater walls show in their lower portions an alternation of pyroclastic deposits and lava flows that pre-date the 1809 eruption, extending back to the Ellittico stage of Etna that ended about 15,000 years ago. This pre-1809 succession is cut by a vertical fissure about 2 m wide, which is partially filled by lava and marks the position of the dike that rose to the surface at the beginning of the 1809 eruption. This is actually how most flank eruptions at Etna begin - magma rises through a narrow dike that propagates downslope; the initial activity occurs at numerous small vents along an eruptive fissure, forming "curtains of fire" as in many eruptions on Hawaii. As the eruption continued, the activity began to concentrate in fewer places where it grew more intense, blowing out pre-existing material and thus forming larger craters. The deposit laid down during this phase contains abundant lithic blocks consisting of the pre-existing material blown out as the craters enlarged; intermittent episodes of lava fountaining produced deposits of more or less welded scoriae that transformed sometimes into clastogenic flows. In the final phase of the eruption, intermittent explosions threw out large lithic blocks which lie scattered on the surface around the craters.
I made many visits to the 1809 craters starting in August 1989, but most of the photographs on this page were taken in June-July 1999. During the devastating eruption that started in late October 2002, new vents opened very close to the 1809 craters; some of these show a very similar sequence of events as those documented in the spectacular outcrop of the largest of the 1809 craters.

The south wall of the uppermost of the large 1809 craters is seen in this series of photographs taken in late June 1999. A general view of the crater is shown at left, with the Northeast Crater (about 3.5 km away) forming the skyline; to the left of it rises the rounded crest of the Pizzi Deneri. The center and right photos zoom in closer on the revealing stratigraphy exposed in the crater wall, showing a succession of older deposits and the dike that rose vertically to the surface, feeding the deposits emplaced at the top of the succession

More detail is visible in these photographs. Note the massive lava flow, about 10 thick, probably erupted at the beginning of the 1614-1624 eruption, overlain by an undated scoria deposit; both were cut by the 1809 dike. Toward the top the fissure occupied by the dike is seen to enlarge into a funnel-shaped feature and a small lava flow extends from it to the left, forming the basal deposit of the 1809 eruption. This flow was probably fed from intense fall of fluid spatter from lava fountains forming a "curtain of fire"; later activity concentrated at the crater in the foreground, blowing out much of the pre-existing material and producing a deposit rich in lithics (which are actually fragments of the blown-out material) and fresh scoriae. No large cone was formed during this eruption, which was of a relatively short duration in this place and subsequently concentrated at vents lying still further downslope

Left: the largest of the 1809 craters as viewed from its east rim in September 2003, nearly one year after a new eruption which opened new vents very close to the 1809 craters but fortunately did not destroy the spectacular section exposed within the latter Center: funnel-shaped extension of the feeder dike of the 1809 eruption exposed in the north wall of the largest crater formed during that eruption. Photo taken in June 1999 Right: a view from the north rim of the largest of the 1809 craters into the second largest crater which lies immediately to the north. Although the feeder dike is less well exposed in this crater, the stratigraphic succession in the crater walls is interesting. The thick 1614-1624 lava flow, which is promimently exposed in the upper crater is lacking here and thus formed a narrow tongue; in contrast, the 1809 pyroclastic deposit forming the top unit is thicker than at the upper crater. Photo taken in June 1999

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Copyright © Boris Behncke, "Italy's Volcanoes: The Cradle of Volcanology"