During March of 1650 and continuing on for several months, many residents who lived on
the volcanic island of Santorini had been encountering something unusual.
Not only had they encountered the sound of "subterranean roaring" but they also experienced
an unusually high number of earthquakes.
However, despite the fact that the island of Santorini is a massive caldera which produced
its last caldera collapse during the area's bronze age, it was not the source of these
events.
Instead, it originated 8 kilometers to the northeast at a volcano which was at the time
completely unknown to science.
Now called the Kolumbo volcano, this volcano would go on to produce an island forming eruption
and eject substantial amounts of ash which subsequently rained down on Santorini, collapsing
roofs.
Then, a major explosion occurred, causing the island to collapse into a caldera.
This explosion released voluminous pyroclastic flows and tall tsunamis which then raced towards
the coastline of Santorini, causing a large amount of destruction in an event which likely
somewhat resembled the 2022 eruption of the Hunga Tonga Hunga Ha'apai volcano.
Although the Kolumbo volcano has not erupted since, this is to be expected as unlike the
neighboring Santorini volcano, the average time between distinct eruptions at Kolumbo
is greater than 10,000 years.
Thus, since it has only been a few hundred years since its last eruption, you might think
that Kolumbo does not pose much of a hazard.
However, based on new findings, in my opinion the Kolumbo volcano is already theoretically
capable of producing its next volcanic eruption.
Let me explain.
Before this paper was released, it was only believed that the Kolumbo volcano had a magma
chamber at a depth of around 5 kilometers.
And, although not directly stated, it was inferred that the percentage of material in
this chamber that was actually molten, aka the melt, was low.
Generally speaking, a volcano with a very low percentage of melt when compared to the
total overall volume of the magma chamber is highly unlikely to erupt.
However, if the percentage of melt increases when compared to the magma chamber volume,
an eruption becomes all the more likely.
In many cases, there is a minimum threshold that must be reached which largely varies
by volcano that makes a volcano theoretically possible to erupt in the first place.
However, in a new paper which is being referenced on screen, it was discovered that the Kolumbo
volcano instead has a magma chamber at a depth starting at 2.1 kilometers below sea level
and extending to at least 4 kilometers below sea level.
More importantly, this magma chamber was detected to contain as much as 42% melt at its center,
although the paper notes that this might be overestimated by as much as 6%.
However, even with the overestimation, it implies that a section of Kolumbo's magma
chamber has 36% melt.
Based on this figure, in my opinion the Kolumbo volcano is already theoretically capable of
erupting again.
However, this fraction was noted only for the center of the low velocity anomaly, as
other sections of the suspected magma chamber may have a much lower percentage of melt compared
to their volume.
Regardless, a total of 1.38 cubic kilometers of melt was detected underneath the Kolumbo
volcano, which is slightly less than the dense rock equivalent of material ejected during
its 1650 VEI 5 explosive eruption.
While this information might sound a bit scary it is not an immediate cause for concern.
Volcanoes can remain in a state where they can theoretically produce an eruption but
don't for thousands or even tens of thousands of years.
Thus, given the current knowledge of the Kolumbo volcano and its current activity, it seems
unlikely to erupt anytime soon so the residents on the island of Santorini should at least
for now not worry about the Kolumbo volcano.
However, the shallowness of Kolumbo's magma chamber presents a dangerous hazard.
If for some reason a large amount of seawater was to be introduced to this shallow chamber,
it could result in a catastrophic explosion and tsunami somewhat similar to what occurred
at the Hunga Tonga Hunga Ha'apai volcano on January 15th of 2022.
Thus, although a volcanic eruption from the Kolumbo volcano is unlikely for a long time,
it represents a volcano which during its next eruption, whenever it occurs even long from
now, could theoretically produce an almost Hunga Tonga Hunga Ha'apai like explosive repeat.
Thanks for watching!
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Additionally, I would like to thank Dakota Rose for becoming a channel member on youtube
of GeologyHub!