A fun question: which are the southernmost, most equatorial and northernmost volcanoes in the world? We need to add two provisos here, otherwise this question is impossible to answer: the volcano should be on land (sub-aerial, not sub-marine), and it should not be extinct but be known to have erupted.

I’ll give you a few minutes to think about. Two of them should present no problem. Volcanoes are thick like flies near the equator, but are very sparse close to the poles.

Ready? Number 1 is Erebus (77 degrees South) – no problem there. Number 2 is harder – your answer in the comments, please. And number 3 is that rare mountain: a volcano with a Dutch name and even taller than the (mythical) Zuidwal volcano. (We are happy to see that the VC review of this volcano is among the few sites that have survived google’s culling.) It is the infamous Beerenberg on Jan Mayen island (72 degrees North). The infamosity is because its eruptions are nearly impossible to observe. Most of the time the island is covered in the North Atlantic cloud and fog, and if an eruption were to happen during clear weather, very few people are anywhere near close enough to see it.

(One may wonder whether volcanoes try to avoid the polar regions. There are some 1350 active volcanoes on Earth, which is an average of 1 volcano per 350,000 square kilometer. About 10% of the Earth’s surface is closer than 15 degrees to the poles. So one might expect 10% of its volcanoes there – rather more than just 2! The reason for the lack of volcanoes is that the major active rifts and subduction zone currently avoid the polar regions, that the Arctic is mainly sea and submarine volcanoes tend not to be on the list of active volcanoes, and finally that the Antarctic ice sheet (and probably Greenland’s as well) hides and suppresses volcanic activity.)

Discovery

It is likely that Jan Mayen was the original Svalbard, as named by the Vikings on Iceland. But the island had little or no use to them, was never settled and became forgotten again. Nowadays, the name has been transfered to Spitzbergen, much further north but regrettably non-volcanic.

The island was (re-?)discovered in 1614 and 1615, by several ships. Of course, just finding the island was not enough. The discovery had to be reported to the ship’s owners, and then by the owners to the official channels. The first one to find it reported it the funders, but they kept its secret for commercial reasons. The second and third ship arrived (together) while the first ship was still there. All three ships were Dutch. A year later, an English ship followed. By now the island had been given four separate names, including the old Viking one. The French added a 5^th one 20 years later. None of these names were to stick.

All of the ships made maps, of varying accuracy, and these indicated names for separate features. One of those features (a small promontory) had been named ‘May’ after the captain of one of the ships. A few years later, this map was redrawn to become part of the famous Bleau atlas (the most famous atlas you have never heard of). On this map, the name ‘Ioanne Mayen’ was now assigned to the entire island, overruling all other names. (the ‘en’ ending means the same as the ‘ ’s’ in English.) Hence the name ‘Jan Mayen island’, immortalizing Captain Jan Jacobszoon May van Schellinkhout of the ship ‘Golden Cat’. The island was used as a whaling base for the next 20 years, but the whales soon ran out (or swam off) and Jan Mayen Island became abandoned.

Since 1930 the island has been Norwegian, being donated to the country by the League of Nations. Norway has had to repel attempts of hostile take-overs by Germany in 1940 and by Iceland(!) in 1979. The latter dispute was initially about fishing rights. Owning an island gives a nation a 200-nautical-mile economic zone around it. This zone overlapped between Jan Mayen and Iceland. When this area became economically important (i.e. exploitable fish resources), this led to a territorial dispute. Initially Iceland denied that Jan Mayen was an island! It also claimed that Jan Mayen was part of the continental shelf of Iceland. Neither claim seems particularly strong, in hindsight. But the dispute led to a formal, internationally recognized (though not by all countries) definition of an island:

“An island is a naturally formed area of land, surrounded by water, which is above water at high tide. [..] The territorial sea, the contiguous zone , the exclusive economic zone and the continental shelf of an island are determined in accordance with the provisions applicable to other land territory. Rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf.”

Thus, Jan Mayen became an island! The dispute was resolved peacefully (Iceland got a little more out of it than Norway) and the exploitation of the disputed area was shared. The problem has now become relevant in other places of the world, especially the South China Sea where there seems to be less willingness to resolve the claims in the Scandinavian way.

And so Norway became in possession of some fish, a sliver of continental shelf originally from Greenland, possibly oil or gas resources on this shelf, and an active volcano.

The fish may have reason to be concerned. Norway may nowadays be known as a country sympathetic to ‘green’ issues, it has a distinctly ‘non-green’ history. Norwegian hunters arrived on Jan Mayen in 1906 and quickly left the island devoid of life. As elsewhere in the arctic, musk ox and polar foxes were present, but here they were hunted to extinction. There is also little flora (there is an endemic species of dandelion), and even the omni-present polar bears have largely disappeared, although in their case because of global warming which has raised average temperatures here to above freezing – even in winter drift ice now rarely reaches Jan Mayen. To see the arctic in all its life, go elsewhere: Greenland or even Spitsbergen have fared much better.

Jan Mayen Island was declared a nature reserve in 2010; severe restrictions on tourists have made visits nearly impossible. It is not clear what the reserve is intended to protect – the statement was made that it ‘is a poorly understood ecosystem that needs to be protected from risks unknown’. Perhaps ecosystem means the local military base! Sea birds still breed here in splendid isolation and protection, but other bird species are absent because of the lack of vegetation. There is no tundra here – just rock, in places covered by moss and lichen and the occasional lost plant.

There an interesting aside to the story how Jan Mayen became an island. The Kolbeinsey Ridge is named after a valley in Iceland, or rather, to a settler who lived there: Kolbeinn Sigmundarson. In an angry mood (a common problem among the Vikings of a millennium ago, apparently), he managed to crash his ship into a rock in the North Atlantic, and lost his ship, his crew and his life. After this the rock acquired his name: it is a small island north of Grimsey (and located on the Kolbeinsey ridge). In the middle ages, Kolbeinsey was a 700 meter island . Over time it eroded and after 2000 it remained as two rocklets, now only visible at low tide. Iceland used this island (at that time still above water) to extend its 200 nautical mile fishing zone and even built a helicopter landing base to strengthen the claim. (The helipad was lost to the sea 20 years ago.) The redefinition of ‘island’ meant that Kolbeinsey no longer qualified and Iceland had to give up some of its fishing claim. You win some, you lose some. But losing an island must hurt.

Jan Mayen island

Jan Mayen is 700,000 years old, is 54 km long and has an area of 380 square km. The climate is cold maritime, and the North Atlantic weather is fog, wind and drizzle. The island consists of three parts. The larger northern part is dominated by the volcano called Beerenberg, 25 km wide and over 2200 meters tall. Beerenberg may be the tallest mountain in the world with a Dutch name! Towards the southwest is a narrow peninsula, 6 km wide and 600 meter high, connected to the northern part by a 2km-wide low isthmus. The three parts are simply called Nord-Jan, Midt-Jan and Sor-Jan. Sor-Jan is in effect a volcanic ridge, up to 700 meter high. Midt-Jan is a lower, narrow ridge which lacks volcanics. It contains a large lagoon on the south side which dries up in summer. Nord-Jan is in effect a synonym for Beerenberg.

Beerenberg is that rare beast, a stratovolcano built from basaltic lavas. The mountain consists of a broad base, rising at an angle 30 degrees to 1500 meters altitude, with a much steeper cone (45 degree) on top forming the summit. The reported height of 2277m seems to come from quite an old measurement. There is no recent confirmation of this value and the only topographic summit map I have found doesn’t reach quite so high. There is a volcanic ridge extending to the northeast, terminating in cliffs with a low platform near sea level (Nordkapp) which is from more recent volcanics.

Jan Mayen Island can be seen as a 50-km long volcanic fissure (or two offset fissures, one for Sor-Jan and one for Nord-Jan), with a single volcano (Beerenberg) superposed. The inhabited (if not fully habitable) part of the island is the Sor-Jan peninsula. The main town is called, somewhat optimistically, Olonkin City. It has a year-round population of 15 men and 3 women (that was in 2019). People are allowed to live on the island for a maximum of one year.

The microcontinent

Jan Mayen is the tip of an iceberg. Look under water and a complex region surfaces. To the south, a thin ridge extends 300 km towards Iceland, eventually ending in the Jan Mayen trough. This sliver is called the Jan Mayen Ridge; it has a flat top of 10-30 km wide. On the north side runs a fault zone, the West Jan Mayen Fault Zone, which frequently has minor earthquakes, such as in the last few weeks, or even major ones such as the magnitude 6.4 in March this year. Towards the northeast runs one of the Atlantic mid-oceanic rifts, the Mohn’s Ridge. It terminates at the fault zone, jumps west and continues there as the Kolbeinsey Ridge which connects to the north coast of Iceland. Southwest of Jan Mayen runs another fault zone, called (you guessed it) the East Jan Mayen Fault Zone. Far east it connects to yet another Atlantic mid-oceanic rift (the Atlantic is full of them), named the Aegir Ridge. This one is inactive.

Clearly, interesting things have happened here.

Some 50 million years ago, this was the last connection between the American and Eurasian continents. Further south, the two had already separated, and now the division was reaching the north. The split happened along the Aegir Ridge: here was where Norway and Greenland separated. It was accompanied by a brief flood basalt eruption on the Greenland side. The future Jan Mayen Ridge remained part of Greenland. Eventually, the Aegir Ridge had run its course: spreading slowed dramatically 43 million years ago.

Now a new spreading centre formed along the Greenland coast. This became the Kolbeinsey Ridge, and 25 million years ago it split off a sliver from Greenland. This happened with a much lesser fanfare of volcanics. The split fragment consisted of continental crust with a covering of the older flood basalt lavas, but it had become stretched and thinned during the rifting. This thinning caused it to sink below the waves. The spreading was slow, but sufficient to move the sunken sliver away from Greenland: it became a lost microcontinent, the Jan Mayen Ridge. It lies currently 500-1000 meter below sea level. Oil and gas reservoirs are considered likely, due to the close geological relation to the Norwegian continental shelf with its (now heavily depleted) oil deposits. But although some licenses have been issued, no discoveries have yet been reported.

The Mohn’s Ridge became a bit an orphan in all this. It originally was the northern end of the Aegir Ridge. When the Kolbeinsey Ridge developed, the new oceanic crust moved the Aegir Ridge eastward and left the Mohns Ridge stranded. It remains a spreading centre, but a very slow one. The separation between the two spreading regime became the West Jan Mayen Fault Zone: it accommodates the different movements, and is a transform fault which delineates one of the borders between the North American and Eurasian plates.

Jan Mayen Island lies in a fascinating region! But it also exists in splendid isolation: everything else is deep under water. And of course, all eyes are drawn (on a rare clear day) to the beauiful stratovolcano which dominates it.

Beerenberg

Whilst all of Jan Mayen has a volcanic origin, the main volcano is the impressive Beerenberg, the 5th highest volcano in Europe. As already mentioned, it is also the northernmost active volcano in the world (discounting any beneath sea level). The central crater (called Sentralkrateret – more a description than a name) is 1 km wide, is covered in snow, and is the source of the Weyprecht glacier which flows through a breach in the crater wall. It is one of a number of impressive glaciers, several of which until recently reached the sea. Now, only Weyprecht still does.

Until 1970, Beerenberg was not considered an active volcano, despite old reports of minor eruptions. The oldest such report was from 17 May 1732, when a Dutch sailor on an anchored ship saw a small eruption with flames and black ashes. It came from the south-eastern slope of Beerenberg and lasted for about 28 hrs. The same area had another small eruption on 29 April 1818, this time observed by the British polar explorer (and whaler) William Scoresby, Jr. He saw a smoke column rising to 1 km. Neither event produced lava. It is worth noting that similar events in the winter could not have been seen, and it is quite likely there have been more, but unobserved, events.

Beerenberg received little attention after this, not being designated as an actve volcano. But on 18 September 1970, that changed. It started with a magnitude 5 at the north side of the island. This was followed, probably immediately, by a large eruption. The eruption was not seen by the local observers at the weather station, who were affected (as usual) by snow and fog. In fact, they did send out a patrol (by car) to see the effects of the earthquake, but the patrol did not see anything, in part because they went to the northwest corner (where there was a road) while the eruption was in the inaccessible northeast. The eruption cloud was subsequently found on satellite images. In southern England, the following days showed volcanic colours in the twilight skies: the ash and dust had spread across the Atlantic.

On 19 September, there was another felt earthquake on the island. The pilots of a plane which had taken off from Jan Mayen on the way to Norway saw the mushroom-shaped eruption cloud – although they did not recognize it as such. Early the next morning (3 am, 20 September) a Japanese plane saw a cloud rising to 10 km, finally recognized it for what it was, and reported the eruption. They were shortly followed by similar reports from other aircraft. There may have been further explosions between 18 and 21 September: it is hard to tell with such an obscure(d) volcano! The weather station, 30 km away, was quickly (and briefly) evacuated, although in hindsight this had not been necessary.

On 21 September, investigators arrived and finally found the eruption in progress. The eruption occurred in four locations along the northeast coast, over a distance of 5 km. Lava fountains were 200 meters high and the lava flowed in four streams in to the sea. The lava extended the shoreline by 1 km, and the depth of the sea reduced by 100 meter. It seems, however, that this was not just due to the lava. There may have been a collapse along the coast, or perhaps a rotation of the coastal block with the on-land part sinking and the part lower down rising. The lava flows lasted until mid-October – it may have continued until December but the weather was too poor (or rather too normal) to investigate.

There was a final observation of smoke on March 16 and 23, 1971, in both cases after an earthquake. On the second date, there was also some fumarole activity on the southern side of Beerenberg. With that, the eruption had ended. The lava volume is estimated at 0.5 km³, but this seems quite uncertain.

A new earthquake swarm occurred in January 1973, with more than 300 detected events, which resulted in an explosion crater next one of the 1970 eruption sites which was found in the following summer. Widespread fumarole activity was seen in the area that summer. However, whether this constitutes an eruption or an after-event is not so clear. Many sites list an 1973 eruption, and one AI even tried to tell me it was enormous (being confused with 1970 – it is all the same to an AI), but this is all it was. It seems better to describe it as a late hick-up.

Beerenberg was by now thought to erupt on average around once per century. Thus, 1985 brought a surprise when on Sunday 6 January an earthquake swarm with several high M4 events heralded a new eruption. It happened at extreme northeast corner of the island. The weather was clear enough that a red sky could be seen from the settlement, 30 km away. Commercial planes flying overheard early the next morning reported seeing lava flows. A plane was arranged to fly from Reykjavik to observe the eruption. It arrived in the afternoon, just after the eruption had ended. A photo from this excursion is shown below. The observers saw three new craters, one of which emitted the ash plume, while a white plume at the coast showed where lava had reached the sea. But the craters no longer had lava flowing out of them, although there was still lava visible inside the craters. The total lava volume of the eruption was probably no more than 0.01 km³.

Beerenberg volcano is in fact fairly active, although not at the level of some of the Icelandic volcanoes. Ancient eruptions are recorded in the Greenland ice. Fumarole activity in the crater is common, but the central crater is probably currently blocked by a cold plug, and all recorded eruptions have been from fissures in the flanks. But there have been holocene eruptions from the summit and they could occur again. Sor-Jan has not been active in the holocene and is probably a bit like the Reykjanes peninsula – active when it wants to, quiet when it doesn’t, and without any central volcano.

De-spotify Jan Mayen

Why is Jan Mayen’s Island here? It is sitting at the end of a spreading centre but those normally remain submerged. Iceland is a counter example where a spreading ridge rose above sea level, but that is attributed to a hot spot. It has therefore been suggested that Jan Mayen too has a hot spot underneath it. This hotspot even has its own wikipedia page which neatly summarizes the evidence for it – it is a very brief page! A mantle plume has been mentioned, similarly with limited evidence. There is an indication for one underneath Iceland and underneath the Kolbeinsey ridge, but not underneath Jan Mayen Island. The sea floor bulge that should accompany a mantle plume (present around Iceland) is absent from Jan Mayen. That leaves the explanation for this isolated volcanic spot up in the air!

Jan Mayen’s location is part of the mystery. It lies at the place where the Jan Mayen Ridge connects to the Mohn’s Ridge. One is a sliver of Greenland’s continental shelf, the other is an oceanic spreading centre. Which one does Jan Mayen belong to?

Drilling has shown that the Jan Mayen Ridge consists of sediments (not unexpectedly) without lava – there are some tephra layers but these may come from Jan Mayen. In contrast, Jan Mayen Island is mainly volcanic. Any sedimentary basement lies deeply buried. The volcanic nature shows that Jan Mayen Island is part of the Mohn’s Ridge, more than it belongs to the Jan Mayen Ridge. This relation is strengthened by the fact that its volcanic activity is stronger in the north, closer to the Mohn’s Ridge. The fissures show the same relation, as the lines of the fissures are along the same angle as those of the Mohn’s Ridge.

But that begs the question why there is a major volcano on the Mohn’s Ridge above sea level, when the rest of this ultra-slow ridge has little volcanic activity. A finger can be pointed at the Fault Zone which terminates the Mohn’s Ridge, and which may allow magma to come up more easily. Another finger may point at the continental crust of the Jan Mayen Ridge which ends here as well but from the other side. This continental block may channel magma around it towards Jan Mayen Island. The lava production of Jan Mayen Island is about three times higher than a mid-oceanic ridge of the same length would do. Channeling of magma produced over 100-200 km length would explain Jan Mayen Island and its Beerenberg volcano.

Beerenberg may be the best protected volcano in the world. It also remains remarkably unknown and understudied. Perhaps these two are not entirely unrelated: it may be difficult to study a volcano you are not allowed to visit. We can be reasonably confident that the next eruption will come as a surprise.

Albert, October 2025

Further reading

• http://jan.mayen.no/
• http://www.jan-mayen.com/jan-mayen-information.html
• http://volcano.oregonstate.edu/beerenberg
• https://www.jordskjelv.no/seismogram/?station=1250&date=2025-10-11