The Mount Etna volcano in Italy is one of the world's most famed and spectacular volcanoes.
Etna is most famous for its spectacular lava fountains which have reached as much as a
mile in height above its active crater rim.
In fact, Etna is erupting right now, albeit at a low intensity as of the writing of this
video, via a vent just east of its summit.
This ongoing eruption isn't all that unusual, as Mount Etna has been almost continuously
erupting for several thousand years.
Mount Etna began forming 500,000 years ago, when vents several tens of kilometers to the
southeast of its modern summit were underwater.
These vents produced a series of submarine volcanic eruptions in the Mediterranean Sea.
These underwater eruptions created rounded blocks of basalt lava which are termed pillow
basalts.
Eventually, the center of volcanism shifted to the nothwest.
Then, the composition of Etna's lavas changed, and eruptions began building a stratovolcano
out of overlapping layers of ash and lava.
One major explosive eruption occurred around 82,800 years ago, being comparable in size
of tephra ejected to the 2022 eruption of Hunga Tonga Hunga Ha'apai, with the eruption
from Etna ejecting 10 cubic kilometers of volcanic rock and being assigned a volcanic
explosivity index rating of a 6.
A second notable eruption occurred sometime between 10,000 and 100,000 years ago, but
the exact age of this event is unclear.
It might even be associated with the aforementioned large eruption.
The eruption in question caused a portion of the eastern side of Mount Etna to collapse
and slide into the ocean.
This occurred in a similar way to the 1888 eruption of the Bandai volcano in Japan, leaving
behind a similar collapse scar which is today known as Valle del Bove.
However, it is also worth noting a differing theory.
This collapse scar may not have formed through a large volcanic eruption but rather through
gradual hydrothermal alteration of the flank, which eventually collapsed due to a small
eruption or no eruption at all.
A similar noneruption related collapse scar can be seen at the extinct Mount Taylor volcano
in New Mexico.
The next major eruption from this volcano occurred in 1500 BCE, when a large eruption
produced at least a cubic kilometer of tephra.
A similarly large event albeit an order of magnitude smaller occurred in 122 BCE via
a plinian eruption which produced a sustained eruption column.
Between these large eruptions there likely were dozens of other smaller eruptions that
didn't get recorded by local authorities, as they weren't considered significant events.
This is a reasonable assumption given the near continuous volcanic activity which has
been witnessed at the mountain during the past several hundred years.
Another notable eruption occurred in 1669, when a vent formed 14 kilometers to the south
of the main summit.
This eruption was only moderately explosive, but produced long travelling lava flows which
would go on to destroy a number of towns.
The largest explosive eruption from Mount Etna in the last one thousand years took place
in 1787, when a VEI 4 explosive eruption occurred.
Since then, such as during 2021, many tall lava fountains have occurred, some of which
have been nearly a mile or slightly more than a mile in height above Etna's crater rim.
Here is some footage from the 2021 eruption.
The reason why Mount Etna is able to produce such high lava fountains relates to the presumably
high gas content its magma contains when compared to other volcanoes of a similar composition.
For the last several hundred years, Mount Etna has had near continuous eruptions.
Occasionally, large explosions close to the summit craters will make the news as they
violently eject pieces of lava into the air.
Eruptions at Etna largely result in hazards confined to Mount Etna's edifice but exceptions
do exist as shown by historical eruptions such as during 1669.
Recent eruptions at Etna have largely been of a small to medium size, with activity mostly
occurring via strombolian or vulcanian eruptions.
This is in contrast to its much large plinian eruptions like what occurred in 1500 BCE.
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Additionally, I would like to thank Jessica M. Kandal, PhD, for becoming a channel member
on youtube of GeologyHub!