M6.5 earthquake strikes remote Norwegian island

We look at the fascinating setting of this event

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A magnitude 6.5 earthquake shook the remote Norwegian island of Jan Mayen on March 10, 2025 at 2:33 AM.

Jan Mayen is an extremely isolated island in the central Norwegian Sea. The island sits well above the Arctic Circle at 71°N. It lies 600 kilometers north of Iceland, 950 kilometers west of Norway, and 500 kilometers east of Greenland. We admit that we were not familiar with Jan Mayen before this earthquake occurred. However, it is a fascinating place: geographically, historically, and geologically.

Figure 1: Photo of the Weyprecht Glacier descending almost two vertical kilometers from the Beerenberg volcano crater to the sea, on Jan Mayen island. Credit: G.L., photo from Google Earth. https://lh5.googleusercontent.com/p/AF1QipMB-7hBBx8Fy8ngxuUiKYYdh0eni4nun-wJFgLT=h1440

Because of its remoteness, many early sailors who passed by thought they were discovering the island for the first time, and took the opportunity to name it. Thus, the island has been variously called Hudson’s Touches, Isle de Richelieu, Sir Thomas Smith’s Island, and Trinity Island, among others. The name that stuck — Jan Mayen — comes from a Norwegian Dutch whaling captain, Jan Jacobszoon May van Schellinkhout. (Thank you to two readers who gently corrected this error.)

Whether or not Jan was the first to discover the island, he has left his mark on history. Ultimately, Jan Jacobszoon May van Schellinkhout lent his name not just to the island, but by geological descent to a number of other features: we now have, in addition to Jan Mayen Island, the Jan Mayen Fracture Zone, Jan Mayen Fault Zone, Jan Mayen Plateau, and the Jan Mayen Microcontinent.

Although Wikipedia reports that the permanent population of Jan Mayen is currently zero, the USGS has received two felt reports, indicating local shaking intensities of VII and VIII. These are probably two of the eighteen-or-so members of the Norwegian Armed Forces and Norwegian Meteorological Institute who reportedly stay there over winter, or from other temporary visitors. In any case, this is an extremely high response rate for the DYFI system! If any of our readers knows anyone on the island, please tell them thank you, and let us know in the comments!

(On a totally unrelated note, John Carpenter’s classic horror film The Thing begins with the discovery of an alien spacecraft by a Norwegian geological research team operating out of an isolated base in Antarctica. The film was actually shot in the Arctic. Food for thought…)

Earthquakes and faulting

Earthquakes often occur near Jan Mayen. The island lies along the great divergent plate boundary between the Eurasia Plate and the North America Plate. As with all spreading systems, this one is composed of two basic structures: magmatic spreading centers, where new oceanic crust is born as the plates on either side pull away from each other, and transform faults, which connect the ends of spreading ridges and allow free sideways motion by strike-slip faulting. The extensions of the transform faults beyond the active spreading ridges are called fracture zones, and are geologically dead.

This latest earthquake occurred on one of these transform faults: an ~200-km-long fault system that connects a spreading ridge to the southwest — the Kolbeinsey Ridge, which reaches down to Iceland — to Mohn’s Ridge to the northeast. This relatively small transform fault has produced a pretty impressive number of earthquakes over the last couple decades: in addition to the latest M6.5, there were two M6.8s in 2012 and 2018, as well as about a dozen other events above M5. The focal mechanisms of these events are all oriented to match left-lateral slip on the transform fault connecting the two ridges. The two larger earthquakes in 2012 and 2018 occurred further to the northwest, away from Jan Mayen Island.

Figure 2. Tectonic context of the May 10 M6.5 earthquake at Jan Mayen. Arrows show plate motions relative to Eurasia. Disregard the arrows to the right of Kolbeinsey Ridge. Earthquakes above M6 are labelled. Orange dotted. line shows the Jan Mayen Fracture Zone, which extends beyond the ends of the Jan Mayen Transform Fault.

The map above also shows a M7.0 event on May 6, 1951 that is reported in the ISC catalog. However, the actual record for this event indicates that it is extremely questionable, and it should probably be disregarded without further confirmation. Interestingly, a much smaller, but much more devastating, strike-slip event — the 1951 El Salvador earthquake —  also occurred on May 6.

While the transform fault is clearly responsible for the big earthquakes, there is actually a lot more to look at here, geologically speaking. The transform fault sits in the middle of the Norwegian Sea, and we might expect oceanic crust on both sides. However, the transform fault actually cuts across the tip of a fragment of old continental crust, most of which is submerged underwater today — this is the Jan Mayen Microcontinent. (Thanks again, Jan Jacobszoon May van Schellinkhout.)

The stranded Jan Mayen Microcontinent

This little piece of crust once used to snuggle comfortably between Greenland and Eurasia, back when they were connected together. It was then progressively abandoned, cast into its current far-flung location beneath the Norwegian Sea by a series of unfortunate tectonic events. For the interested, an extremely detailed look at this story can be found in Blischke et al. (2021); we have tried to condense the tale down somewhat from that reference.

Figure 3: Schematic tectonic map of the Jan Mayen area. Image from Wikipedia, by Mikenorton. https://en.wikipedia.org/wiki/Jan_Mayen_Microcontinent#/media/File:JanMayenlocation.PNG (We regularly run into useful. tectonic illustrations by Wikipedia contributor and structural geologist Mikenorton, and find them very helpful!)

About 55 million years ago, the microcontinent was first rifted off of Eurasia as the spreading ridge that birthed the Atlantic Ocean propagated northward. At this point, the future microcontinent was just an undistinguished edge piece of the North America Plate. The original spreading center was abandoned about 21 million years ago, when rifting leapfrogged progressively westward, chopping up the Jan Mayen Microcontinent as it moved. Today’s spreading ridge west of the microcontinent was eventually established about 15 million years ago. Since then, continued spreading has separated the microcontinent from Greenland and left it in its current stranded (lonely?) position in the middle of the Norwegian Sea. For speculations on why this happened, we refer the reader to the reference above.

Volcanism

The highest point of Jan Mayen is the summit of an active volcano, with the delicious name Beerenberg. (Sadly, Beerenberg does not host beer; instead, it is apparently named after the polar bears spotted by whalers in the 1600s.) Beerenberg is distinguished by being both the northernmost active volcano that isn’t under water, and by being Norway’s only active volcano. (The even more northerly underwater volcanoes occur along the Gakkel spreading ridge, which crosses the Arctic Ocean seafloor.)

While Beerenberg is physically impressive, it is not particularly eruptive, with the last recorded small eruption happening in 1985. Since the mid 18th century, historic eruptions have been relatively minor affairs occurring only along the low flanks of the great volcano. The volcanic origin of the rest of Jan Mayen is evidenced by the numerous craters still dotting the landscape and the gray-and-red hues of the exposed rocks. These fresh craters are another sign of the youthfulness of the volcanism, as they would have been obliterated by landed glacial ice during the last glacial maximum about 20,000 years ago. In fact, a detailed recent field study of the glacial geology of Jan Mayen (Lyså et al., 2020) clearly showed that the entire island was swamped beneath an ice cap during the last glacial period. That paper contains a very interesting field photo of glacial striae, with a 35 CENTIMETER LONG KNIFE for scale. We assume that polar bears are involved in the decision to carry a Crocodile Dundee type knife in an area where the dominant vegetation seems to be moss…

Figure 4: Field photograph of glaciation striations on Jan Mayen, with inexplicably giant knife for scale. Figure 8F of Lyså et al. (2020).

As seen in the intro photograph, the summit caldera of Beerenberg is breached to the north, but instead of lava spilling forth, a cascade of glacial ice called the Weyprecht Glacier flows slowly down from the crater to the sea. If the summit vent were to reawaken, there would be an impressive battle between magma and glacial ice.

Figure 5: Some volcanic topography at Jan Mayen. Inset at top left shows remnant cinder cones. Inset at bottom right shows the Weyprecht Glacier descending to the sea from the large summit caldera.

Clearly, at some point a volcanic system developed along the northern edge of the Jan Mayen Microcontinent, and erupted enough material to form a long island above sea level. When did this happen?

Well, Jan Mayen is entirely volcanic and locally active, and all of the exposed rocks contained a fossilized magnetism orientation that matches the current magnetic field — so they must be younger than 700,000 years old. Isotopic studies indicate that the lavas erupted within the last ~500,000 years.

So, why is this volcanism happening? A few different explanations have been proposed. Please note that this isn’t a literature survey — it’s just what we dredged up with in our initial paper scrape as we tried to figure out what is happening.

One idea is that Jan Mayen’s volcanoes are simply due to the interaction of two features described above: that the volcanism of Mohn’s Ridge extends a bit too far to the south, into the stranded continental crust. That continental crust is lower density, so the ocean floor is significantly shallower, allowing volcanoes to grow above sea level. This idea could explain why Jan Mayen is elongated to the northeast-southwest, matching the orientation of Mohn’s Ridge. In this model, this volcanism would have presumably started as the microcontinent moved southeastward, until it roughly lined up with Mohn’s Ridge.

Other researchers have proposed that there is actually extra magma supply beneath Jan Mayen, caused by an underlying mantle plume. Because mantle plumes don’t care what is happening above them, this could explain intense volcanic activity in an area where it otherwise wouldn’t usually make sense. However, mantle plumes are also an incredibly convenient get-out-of-jail-free explanation for explaining volcanism in general. We won’t weigh in on this one.

Finally, Morgan and Phipps Morgan mention Jan Mayen in a paper mostly focused on global plate motions. They write: "Jan Mayen ‘is not a hotspot but rather [is] due to channeled asthenosphere flow from Iceland’ (electronic supplement, p. 6).” The supplement does not provide much more information; the goal of that paper was simply to indicate that the Jan Mayen hotspot is not a reliable datapoint to include when constructing a hotspot reference frame. We’re not quite sure what the justification was for discarding it, or if the evidence is simply too thin to include it.

Well, maybe there is no consensus explanation for the volcanism at Jan Mayen — yet. That seems like a good reason to volunteer for a Norwegian geological research expedition to a remote Arctic field base. Just be sure to pack your giant knife, and watch out for shape-shifting aliens…

References:

Blischke, A., Brandsdóttir, B., Stoker, M.S., Gaina, C., Erlendsson, Ö., Tegner, C., Halldórsson, S.A., Helgadóttir, H.M., Gautason, B., Planke, S. and Koppers, A.A., 2022. Seismic volcanostratigraphy: The key to resolving the Jan Mayen microcontinent and Iceland Plateau Rift evolution. Geochemistry, Geophysics, Geosystems, 23(4), p.e2021GC009948. https://doi.org/10.1029/2021GC009948

Elkins, L.J., Hamelin, C., Blichert-Toft, J., Scott, S.R., Sims, K.W.W., Yeo, I.A., Devey, C.W. and Pedersen, R.B., 2016. North Atlantic hotspot-ridge interaction near Jan Mayen Island. Geochemical Perspectives Letters, 2(1), pp.55-67. https://doi.org/10.7185/geochemlet.1606

Gjerløw, E., Höskuldsson, Á., Bartolini, S., Biass, S., Mossoux, S., Gilbert, J., Pedersen, R.B. and Martí, J., 2022. The Volcanic Hazards of Jan Mayen Island (North-Atlantic). Frontiers in Earth Science, 10, p.730734. https://doi.org/10.3389/feart.2022.730734

Lyså, A., Larsen, E.A., Anjar, J., Akçar, N., Ganerød, M., Hiksdal, A., Van Der Lelij, R. and Vockenhuber, C., 2021. The last glaciation of the Arctic volcanic island Jan Mayen. Boreas, 50(1), pp.6-28. https://doi.org/10.1111/bor.12482

Morgan, W.J. and Morgan, J.P., 2007. Plate velocities in the hotspot reference frame. in: Plates, Plumes, and Planetary Processes, eds. Foulger and Jurdy, GSA. https://doi.org/10.1130/2007.2430(04)

Trønnes, R.G., Planke, S., Sundvoll, B. and Imsland, P., 1999. Recent volcanic rocks from Jan Mayen: Low‐degree melt fractions of enriched northeast Atlantic mantle. Journal of Geophysical Research: Solid Earth, 104(B4), pp.7153-7168. https://doi.org/10.1029/1999JB900007