Which Icelandic Volcano Will Erupt Next?

At a surface level, this seems like a fairly simple answer. The Reykjanes volcano. After all, it is primed for yet another eruption to occur. And if not, maybe Fagradalsfjall will come to life and produce an eruption for the 4th year in a row?

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 have 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 Known:

Krysuvik. Had 1 intrusion which failed in 2020 but has produced several strong earthquake swarms in 2023 and 2024. Given the rifting period the Reykjanes peninsula is experiencing, it could eventually widen to the next adjacent volcano towards the east. After all, the western section and edge of Kleifarvatn (Lake) has been producing a suspiciously high number of earthquakes for two years now. However, there is not yet any reason to suspect that fresh magma is present under this specific volcano. Due to the number of sensors in the area, we would know if uplift was occurring there. This is why Krysuvik is the “known”.

The unknown:

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 have occurred. Eldey could technically be in an unrest state right now and we probably wouldn’t know. Eldey is essentially Krysuvik, a potential site of future rifting of the Reykjanes Peninsula, but further to the west rather than east. I am classifying Eldey as an unknown due our lack of an ability to accurately monitor the volcano. I want to note that Eldey during the last major rifting episode on the Reykjanes peninsula produced an eruption around the same time one of Reykjanes’s eruption occurred. During heightened rifting phases multiple volcanoes end up erupting, as we’ve seen already at 2 separate volcanoes, Reykjanes & Fagradalsfjall.

Statistically most likely:

Grimsvotn. Grimsvotn is historically the most active volcano in Iceland. This has averaged out to about once every 10 to 12 years. And what do you know, scientific models which have attempted to explain Grimsvotn suggests that it is approaching a threshold that signaled an increased likelihood of an eruption. As a result, Grimsvotn (if the model is to be believed) can be classified of overdue for an eruption. However, there is no reason to suggest that any significant volcanic unrest 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. Note how many glacial floods (jokulhaups) Grimsvotn has produced in recent years, likely caused by variations in its hydrothermal system overlied by glaciers.

The wildcard:

Hekla. Hekla has also produced frequent eruptions (being one of the most historically active volcanoes in Iceland), but has a unique quality that differentiates it from Grimsvotn. Hekla’s eruptions often occur with little or no warning beforehand. No build up, no significant ground deformation, just the potential of unexpectedly erupting within 30 to 90 minutes warning. This short notice occurred during several of its last 5 eruptions, hence why many warning signs are placed around the volcano asking people to always turn cellular data on when they are near Hekla. (This is in case suspicious activity is detected so alerts are automatically sent to every phone in the region). Hekla has not produced any obvious signs of unrest as of late. But then again, I wouldn’t personally expect any warning signs to occur days, weeks, or even months before its next eruption (but rather, minutes to hours). This is why I am calling Hekla a wildcard.

Which of these would you pick?

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 of Icelandic volcanoes and extent + limitations of current volcanology.

Note: I plan to make a full length video which discusses this topic in further detail.

Feel free to instead suggest another volcano in Iceland as a response to the above question.