The long history of Greece contains records of numerous volcanic eruptions.
In the last 10,000 years, 6 of these volcanoes have produced eruptions.
However, one of these volcanoes stands apart, as few people know of its existence.
Yet, in 1650, it produced the deadliest volcanic eruption within Greece of the last 3,000 years.
This eruption generated a large tsunami, and sent pyroclastic flows across the Mediterranean
sea and onto the island of Santorini, causing much destruction.
The volcano which produced this eruption is called Kolumbo, which is located 10 kilometers
northeast of the island of Santorini.
This video will discuss this submarine volcano, and mention what its future hazards are.
The immediate reason why Kolumbo exists is due to a regional weak spot in the crust.
This weak spot is partially responsible for the volcanic activity on the island of Santorini,
from which it travels in a northeast line for 30 kilometers.
This weak spot allows magma to travel upwards through the bottom of the Mediterranean Sea,
and form a number of volcanic cones.
Kolumbo is merely the most recent of 20 different volcanic cones to have erupted along this
zone of activity.
We aren't exactly sure how old Kolumbo is, but through limited data we can estimate that
it began forming 126,000 years ago.
The initial eruptions at Kolumbo occurred at a depth of 420 meters beneath the Mediterranean
Sea, and were unusually explosive for a submarine volcano.
The reason for this is that Kolumbo contained two different magma chambers at depth with
different compositions.
One of these contained basaltic lava, while the other contains rhyolitic lava.
When these two magma chambers mix, it causes unusually explosive eruptions to occur.
By 80,000 years ago, Kolumbo had grown to within 200 meters of the sea's surface.
Due to the rift zone which fed these eruptions, Kolumbo had an elongated shape which trended
in a northeast direction.
Between 70,000 and 10,000 years ago, four additional large volume eruptions occurred
at Kolumbo.
After this last eruption, the volcano was within 30 meters of the surface of the Mediterranean
Sea.
(pause 2 seconds) After a long period of dormancy followed by
a series of nearby earthquakes, Kolumbo suddenly erupted in early September of 1650.
Initially, the effects of this eruption were difficult to notice, as it only created patches
of discolored water above the volcano.
However, as the eruption continued, its effects became more noticeable.
On September 27th, residents on the island of Santorini witnessed jets of lava and ash
rise from the sea in the distance.
Over the next 36 hours, Kolumbo climbed above the surface of the water, and formed a small
white-gray island.
As the explosions on this island became larger, it generated large volumes of pumice, which
floated towards nearby islands.
Then, on September 29th, a massive explosion occurred.
This explosion destroyed the existing island, and caused the summit of Kolumbo to collapse
downwards by 500 meters.
This event triggered a large tsunami, which then raced towards surrounding islands.
Parts of southeast Ios and northeast Santorini were hit with a 20 meter high wave.
As this tsunami continued onwards, it lost height.
By the time it reached the island of Sikinos, it was 3 meters tall.
Soonafter the tsunami cleared, a series of low density pyroclastic flows became clear
as they traveled outwards from the eruption's center.
These pyroclastic flows then reached the northeast coast of Santorini, causing 70 casualties.
Although the explosive phase of the eruption had ended, low levels of activity continued
until December 26th when the eruption ended.
The eruption which had just occurred had a volcanic explosivity index of 5, which ejected
5 cubic kilometers of lava and ash.
This was the largest eruption to occur in Greece in the last 3,000 years.
Since then, no additional eruptions have occurred from this volcano.
Today, the high point of Kolumbo is 10 meters beneath the surface.
Around the volcano, numerous fumaroles can be observed, indicating that Kolumbo is still
active.
However, it is unlikely to erupt anytime soon.
On average, Kolumbo appears to produce large volume eruptions about once every 14,000 years.
In the unlikely event that it was to erupt again, the main threat would be the risk of
another tsunami.
I recommend that a tsunami buoy be placed around the volcano, to give several minutes
notice to nearby islands.
I hope that you enjoyed this video!
If you would like to request a specific topic, please leave a comment below!
Additionally, if you wish to support this channel, consider becoming a patron on patreon.