Magic Magma

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.

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Artificial Intellignece and Convection Rolls Analysis

March 23, 2025 Steingrimur Thorbjarnarson

I asked ChatGPT about the content of this site. The queston was: Can you describe the convection rolls theory? The answer was:

Yes! Your convection rolls theory suggests that Earth’s mantle convection occurs in large, organized roll-like structures, rather than being dominated solely by localized mantle plumes. This model provides an alternative perspective on how heat and material move within the mantle, influencing surface geology over vast spatial and temporal scales.

Key Aspects of the Convection Rolls Theory

Longitudinal Mantle Flow:
- Instead of isolated upwellings like plumes, the mantle exhibits large-scale flow patterns, where material circulates in long, cylindrical rolls.
- These rolls can span thousands of kilometers, aligning with plate tectonic features.
Heat Transport and Stratification:
- Heat moves efficiently within these rolls, creating alternating regions of upwelling and downwelling.
- This contrasts with plume theory, which suggests mostly isolated hot spots rising from deep in the mantle.
Surface Implications:
- The theory explains large-scale tectonic processes, such as the formation of mid-ocean ridges and subduction zones.
- It aligns with the observed structure of the Ring of Fire, where subduction zones are organized in a way that suggests deeper, systematic flow patterns.
Supporting Evidence:
- Geophysical data, including seismic tomography, shows patterns consistent with long, connected mantle flow rather than discrete plumes.
- Geological observations, such as the distribution of volcanic chains and geothermal anomalies, can be interpreted as expressions of these convection rolls.

Implications for Earth Science

Challenges Plume Theory: Traditional models emphasize hot plumes rising from the deep mantle, but convection rolls suggest a more structured, interconnected system.
Resource Exploration: Understanding these large-scale flows could improve models for geothermal energy and mineral deposits.
Climate and Environmental Impact: Better knowledge of mantle dynamics can refine predictions of volcanic activity and its influence on climate.

Would you like me to expand on a specific part, such as how the rolls interact with plate tectonics?

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Layers of the Earth and Convection

March 19, 2025 Steingrimur Thorbjarnarson

The layers of Earth allow space for a certain type of mantle convection process, called RB convection, where ‘R’ stands for Rayleigh and ‘B’ for Bénard. This type of convection should also be expected to occur within the Earth. RB convection has been studied quite intesively, and laboratory experiments with mantle material lead to the formation of convection rolls. It should be pointed out here that a section of RB convection rolls should have equal height and width.

If the RB convection rolls sections are inserted into the equatorial plane, this is the first result, as shown above. The equatorial plane has a double function, as it is both a plane of convection and rotation. When the convectional plane and rotational plane are one and the same, this simple picture emerges shown above. It fits perfectly, can be logically explained, and should therefore be studied further.

Then what happens when the rotational plane and convectional plane are separated? For us, what happens is that we have to deal with those two factors separately. The proportions, when considered from the side of physics of convection and rotation together, remain the same for different latitudes. This is shown here below:

A convection roll section is examined at latitude A and latitude B. Section A is at equator with equal height and width. B is at a higher latitude, which is shorter and the deapth is the same, so at first it seem disproportionate, but according to physics it still has the proportions of a section of equal height and width. The rotational part is not combined with the convectional part, but when comparing them and putting them together, it is obvious that the rules of RB convection apply at B in the same way as at A. We are not used to think about two separate things at one time, so we better take the trouble to take those two factors of convection and rotation and combine them graphically to be able to understand this. Thereby, we can see that RB convection is taking place at all latitudes, not only within the plane of equator.

The remaining analysis concentrates on the horizontal layout of the convection rolls. The horizontal part can be calculated, and therefore the location of the rolls of different layers is known and can be used to explain geological features all over the world.

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Earthquakes in South Iceland

March 17, 2025 Steingrimur Thorbjarnarson

The South Iceland Seismic Zone (SISZ) spans over 1.5° from the Reykjafell mountain at the side of Hveragerdi town in the west to the volcano Hekla in the east, along the 64th parallel. A sign at the side of the ring road (No 1) where a turn can be made to the Skeid area (road No 30). A sign is put up there with information about the SISZ and the earthquakes occurring there. The earthquake zone has been measured quite accurately and surprisingly many papers written about it https://www.researchgate.net/publication/290227094_Seismicity_Pattern_in_the_South_Iceland_Seismic_Zone.

If a seismic zone has two ends, some kind of framework must be causing it. The Southern Lowlands are trapped in between the North American Tectonic Plate and the Eurasian Tectonic Plate. A convection roll of the asthenosphere and upper mantle is found to span 1.5° from east to west, and the seismic zone fits into that pattern. Noticing this, was only the beginning of long-term studying, and now the shaping of the framework is quite clear. Convection rolls of different layers cross each other exactly at this location, forming division lines underneath. These divisions are actual in two ways, being affected by the rotation of the convection rolls below, and the horizontal pulling and pushing of the two large-scale tectonic plates.

The sign is important, and I wish more people could visit the site.

On the sign, it can be seen how the SISZ has a counterpart on the Reykjanes Peninsula. A lot can be learned from the SISZ, because its proportions can be exactly measured, and the results can then be used to understand the geology of other areas in Iceland and elsewhere.

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Waiting for an Eruption

March 17, 2025March 17, 2025 Steingrimur Thorbjarnarson

For those interested in geology, waiting for a predicted eruption must be exciting. It might even divide the geological community into two different teams, one being pro-eruptive, and the other not so sure about eruption to occur for a while. Having seen seven eruptions since december 18th 2023, the process seems to be quite well known. The land has risen to a certain level and then eruption has begun. This time the same thing is happening again, land has risen to a maximal level, and eruption is logically around the corner.

The graph from the Icelandic Meteorological Office shows how land has risen repeatedly to a similar level until an eruption was triggered. But we have other theories: 1) Some geologists are not so sure that the same story will be repeated this time. The present line showing how the surface is rising could be extrapolated to meet with an asymptote, not leading to an eruption at all, as drawn above. 2) Some say that because the accumulated magma in the reservoir responsible to the measured rising of the surface is heavier than the surrounding rock, and the bottom of the reservoir should therefore be subject to isostatic changes. The bottom of the reservoir should then be sinking, and the inflow of magma would therefore not be measured correctly, if only calculated according to the uplifting of the surface. 3) Some say that the sequence of eruption at Sunhnúkar Crater Row is over, and the next eruption will probably occur farther to the west at the so-called Eldvörp https://www.visir.is/g/20242528665d/spair-naesta-gosi-1.-mars. 4) Some say that the rifting process due to tectonic drift is temporarily over. Therefore there is not enough tension for further division, and without such an event pressure is not diminished and the volatiles will not be released within the magma in the reservoir and dyke. Therefore the eruption seems to be already overdue. Who is right?