Which volcano in Iceland will erupt next?
At a surface level, this seems like a fairly simple answer; the Reykjanes volcano.
After all, it has erupted 4 times in 4 months, and there is no reason to suspect that it
won't erupt a fifth time within the next 30 days.
But, suppose an eruption for some reason does not occur.
Then, the next most likely volcano to erupt would be Fagradalsfjall, which has erupted
once each year during 2021, 2022, and 2023.
If this pattern holds, Fagradalsfjall could very well erupt again in 2024.
However, to make this a more interesting mental exercise, let’s completely remove those
two volcanoes from the above question.
With 32 other volcanoes to choose from, which do I think has the highest likelihood of being
the next volcano to erupt in Iceland?
Although there is no way to be sure in the long term, I wish to highlight 4 candidates.
The first candidate is what I am referring to as "the known"; the Krysuvik volcano.
During the infrequent episodes of greatly increased rifting on the Reykjanes peninsula,
several volcanoes erupt at a high rate in a several decade to several century long timespan.
There is usually a definable center of activity when this occurs, which gets less and less
active the further you get from the center.
This very pattern can be seen during the current ongoing rifting phase which is seemingly centered
in the eastern section of the Reykjanes volcano.
On the eastern periphery of the ongoing rifting is the Krysuvik volcano which as a result
of this activity produced a single magmatic intrusion that failed to reach the surface
during October of 2020.
Krysuvik has also been the site of at least 3 definably magmatic earthquake swarms since
the beginning of 2020, and has regularly produced a surprisingly high number of earthquakes
west of Lake Kleifarvatn.
However, there is not yet any reason to suspect that fresh magma is present under Krysuvik,
and due to the number of sensors on this complex we would know if uplift was occurring there.
This is why Krysuvik is the "known".
Towards the west, the closest volcano to one which has produced an eruption during the
current phase is Eldey.
Eldey has produced slightly less but still fairly numerous earthquakes since 2020.
However, we don’t have the ability to measure underwater ground deformation and most sensors
are too distant to detect any magmatic caused tremors if one was to occur.
Eldey could technically be in an unrest state right now and we probably wouldn't know about
it.
Eldey during the last major rifting episode on the Reykjanes peninsula produced an eruption
around the same time one of the Reykjanes volcano's eruptions occurred.
I am classifying Eldey as an unknown due to our lack of an ability to accurately monitor
the volcano.
Third, we have the statistically most likely volcano, Grimsvotn.
Grimsvotn is by far the historically most active volcano in Iceland, having erupted
a whopping 70 times since Iceland was settled.
Its rate of eruptions has averaged once every 15 years, and it has been 13 years since its
last eruption.
And what do you know, one scientific model suggests that Grimsvotn has already surpassed
a threshold that signals an increased likelihood of an eruption occurring.
As a result, Grimsvotn (if the model is to be believed) can be classified as overdue
for an eruption.
However, there is no reason to suggest that any significant volcanic unrest currently
is ongoing at Grimsvotn.
If just simply represents the most likely volcano in Iceland to experience a heightened
episode of unrest in my opinion outside of the Reykjanes peninsula.
My fourth option is the wildcard known as Hekla.
Hekla is the third most active volcano in all of Iceland with 25 eruptions during the
last 1,000 years.
Hekla, much like Grimsvotn is also considered overdue for an eruption as between 1970 and
2000 it erupted at least once a decade.
Long term uplift all the way back in 2006 surpassed the levels Hekla reached before
its 2000 eruption and yet no eruption has occurred since then.
While there are currently no signs that Hekla is experiencing a heightened level of unrest,
this volcano has a unique quality which makes it a wildcard.
Simply put, all of Hekla's eruptions only produce signals that warn of an imminent eruption
between 23 and 80 minutes before it occurs, with absolutely no unusual activity before
this period.
This short notice occurred during its last 4 eruptions, hence why many warning signs
placed around Hekla ask people to always turn cellular data on when they are near this volcano.
Thus, Hekla could hypothetically erupt at any time and we would not potentially know
about it until as little as 20 minutes beforehand.
Which of these would you pick?
Be sure to comment down below, and feel free to pick one of the 28 other Icelandic volcanoes
which I did not mention.
There is no right or wrong answer.
We cannot predict volcanoes long term, so I think this will be a fun exercise to display
the unique nature of Icelandic volcanoes along with the extent plus limitations of the current
science of volcanology.