So says Dr. Pall Einarsson (autotranslated), and he (along with other Icelandic volcanologists) should know!
But what is under Hofsjokull glacier?
Nobody suspected anything unusual about Hofsjokull, third largest glacier in Iceland, until 1974, when satellite images showed “on low sun angle imagery of Hofsjokull, the outline of a probable central volcano can be seen delineated on the northwest part of the icecap.”
There are nearby geothermal features and associated fissure systems (some showing lava that erupted after the last ice age ended), so it’s an active volcano.
It’s big, too. Per the Hjartardottir and Einarsson PDF:
Radio echo-soundings on the glacier show that the Hofsjökull central volcano has a 6 – 7 km wide and ~600 m deep caldera, which is covered by the Hofsjökull glacier…
Iceland’s volcanoes tend to make their presence known quite forcefully, so how did this roughly 4-mile-wide, 2000-foot-deep caldera go unnoticed for well over a millennium by its human neighbors?
In the machine translation of that linked article at the top, Dr. Einarsson is quoted as saying, “This is an active volcano, but probably one of the laziest of the active volcanoes in Iceland. There are no known large eruptions from this volcano, but several small lavas have flowed since the ice age….”
Hofsjokull is remote, too, located pretty much dead center in the island and well away from any permanent settlements.
And the glacial conditions are rough.
Cue the guest video! Self-described “budding glaciologists” filmed their visit to the glacier last year:
They’re in it for the drumlins, but just think of the huge gaping, silent maw below!
The folks at Volcano Cafe get excited about it:
…. It can hold its own against Katla, Hekla, Grimsvötn. This secretive, hidden mountain, so poorly known that it has no name other than that of the glacier, is the largest volcano in Iceland…
Not every source I found agrees with that last point, but Hofsjokull Caldera certainly is one of Iceland’s biggest active volcanoes.
Yet the volume of lay-level information on it that I could find in an online search is hardly more than what I dug up for yesterday’s post on the Bonn-Oberkassel Dog.
There doesn’t even appear to be online video of the 2013 glacial outburst flood!
This is actually good, since it affected no one.
However, if and when that subglacial central volcano wakes up, it will be Eyjafjallajokull 2010 all over again for North Atlantic air traffic.
And someone will make a beautiful video of it.
Here are some links to get you started on your own attempts to understand this quiet, unassuming caldera that keeps to itself underneath a big glacier in Iceland’s central highlands (but beware the ice caves!):
- Catalogue of Icelandic Volcanoes page.
- Global Volcanism Program page
- Dr. Wikipedia.
- A. Hjartarson, University of Iceland, When did Hofsjokull last erupt? (autotranslated)
Featured image: TommyBee via Wikipedia, public domain.
Flight To Wonder 