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April first, 2025, the dyke responsible for the recent eruptions got active again. New intrusion of magma resulted in an extension to the north-east. It was a surprise, but the alignment can be explained according to the framework of convection rolls underneath.

By showing the context this becomes understandable. The elongation of the dyke took place within an area outside the seismic zone of Reykjanes. The central axis of the seismic zone is marked with a black line, connecting with the straight black line representing the South Iceland Seismic Zone (SISZ). The north-south oriented earthquake faults of the Reykjanes Oblique Zone affect the orientation of the aggregate of focal loci at the southernmost end of the whole dyke. The longer, and new section of the dyke follows the surrounding framework exactly. The tectonic drift vectors can not explain the orientation, but local tension is coherent with the shape of the polygon marked with red lines. The Reykjanes Ridge is responsible for the bending of the Reykjanes Oblique Zone. When it comes to the SISZ, the axis is unafected by the ridge within the polygon, so the central axis becomes a straight line. The same features are found in the Borgarfjörður region of West Iceland.

The Reykjanes Ridge is the most prominent geological feature of Iceland. Extrapolating its main trend along the middle of the Atlantic Ocean, it is found that most of the famous spas in Iceland are found at the edges of the two lines marking its location.

Looking into this more closely, the Blue Lagoon is found on a line perpendicular to the convection roll. Krauma of Deildartunguhver, the most powerful hot spring in the world, is found on crossings of a small polygon. The new Forest Lagoon near Akureyri is also on a perpendicular line, and the same is true for Geosea of Húsavík. At the other side of Geosea is the Myvatn Nature Baths site, and in the center of the country, Hveravellir is found near the upper convection roll extending from the north. Geysir is found just outside the realms of the roll, but on a perpendicular line. Laugarvatn is located directly ong the line, and Reykjadalur on the main crossings.

This is amazing

The eastern edge of this area can be traced most easily. From the coastline to Reykjadalur the so-called Hlíð marks its edge. But the northern ridge is shaped along a different pair of convection rolls, which happens to coincide with the Reykjanes pair at the 64th parallel. Then we get this drawing:

It fits even better to many of the geothermal sites, except the Myvatn Nature Baths, of course. These two pairs form the two ridges south and north of Iceland. At the latitude where the effect of those two is combined, the division line of drift shifts eastwards.

And the tenth area should be pointed out, namely Skagafjordur and the Fljot area of northern Iceland. Fissures associated with the Kolbeinsey Ridge are found on land, and that supports the idea that convection rolls creating the ridges are found at these locations underneath Iceland.

To understand better the relationship between the two ridges, and the two relevant pairs of convection rolls, one has to learn about the intersection zone of Iceland. The Reykjanes Ridge pair is the upper most one south of Iceland, but is subducted at the latitude of Iceland. The pair for Kolbeinsey Ridge is found just below the 120 km discontinuity.

This is not to be confused with subduction of the crust, as the southern convection rolls are overlaid by the northern ones around the 64th parallel. The section is shown here:

The terms, MORB-hemispheric and MORB-polar describe the Reykjanes Ridge and Kolbeinsey Ridge pairs of mantle convection rolls, respectively.

Three factors can be pointed out when looking at the basic features of Iceland. First, the ridges south and north of the country, second, the volcanic zones, third, the elliptical abyss around it. The elliptical form is disrupted by the two ridges, and the said two ridges are not connected due to the fact that a main volcanic zone, called the East Volcanic Zone (EVZ) appears 3° farther to the east than the Reykjanes Ridge. Theoretically, the two ridges can be extrapolated to a central point of Iceland. Doing so, the point where the join each other appears to be the central point of the elliptical form of the abyss.

The drawing, superimposed on a Google Map and a map with basic information about the volcanic zones, shows this quite clearly in a very simple way. The volcanic zones are marked red with a degree of tranparency, and theoretical extrapolation of ridges with yellow line. This mathematical outline of the Icelandic geological framework is of course quite unique, but can all the same be compared with a range of mathematical coherence in other areas. The distribution of land mass and ocean along equator is probably the most amazing mathematical sequence, where 30° separate the main features repeatedly. This can be explained according to the Mantle Convection Rolls Model, as the convection rolls follow mathematical rules and affect the surface accordingly.

The eruptions taking place now follow the same pattern as witnessed about half a century ago in NE Iceland. In Iceland, we talk about such a sequence of eruptions within one volcanic system as fires (eldar in Icelandic). Down below is a graph from a paper written by Páll Einarsson and Bryndís Brandsdóttir, Seismicity of the Northern Volcanic Zone of Iceland (2021):

The paper is available here: file:///C:/Users/Lenovo/Downloads/Seismicity_of_the_Northern_Volcanic_Zone_of_Icelan.pdf. Black lines indicate dyke formations and the distance from Caldera. The red vertical lines indicate eruptions in the same way. The pattern is very similar to that of the sequence of events at Sundhnjúksgígar of Reykjanes.

The settings of the Krafla volcanic system show how this works theoretically according to the mantle convection rolls model. First this drawing for orientation:

Then another drawing with the polygon enlarged:

Then we can speculate about what happened there. The origin of magma was at the small polygon where the Krafla Caldera is located. The dykes did then form along the NS-axis, all the way to the northern corner of the larger polygon north of the caldera. The rifting occurs due to the fact that the North American Tectonic Plate drifts westwards, and the Eurasian plate drifts eastwards. The polygon marked with wide red lines happens to be located right in between those two plates, and consequently breaks in the middle. The combined effect of magma ascending at the southern corner within the caldera, and the tension induced by the pulling from both sides, results in events like the ones described by Páll and Bryndís.

The lines of the polygon form, according to convection rolls analysis, because two convection rolls cross each other underneath, within two different layers of convecting mantle material. Both of those can affect the surface, due to slip and no-slip effects and the Munroe Effect. Therefore, horizontal drift can take place, as rolls working the same way as the drift will become no-slip rolls, those opposing are in the slip mode. Besides, the heat radiation leads to continuos Munroe Effect process, allowing magma to ascend up through the crust at certain locations, in this case where the two layers combine their division lines in a relatively small area underneath the Krafla Caldera.

The events of Reykjanes are not described here, but there is a lot of material available to look at to compare the Krafla fires of the NE with the new Reykjanes fires of the SW of Iceland.