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It is a step forward to be able to calculate the alignment of the mantle convection cells underneath the crust, and thereby knowing how force is exerted on the tectonic plates from down below. The basics tectonic features of Iceland and many other areas follow the formulas very accurately. I participated in a search for geothermal heat at Skógarströnd of the Snæfellsnes Peninsula, and geothermal heat was found at the farm of Innra-Leiti. The borehole was about 1 km deep and hot water was actually found there and registered. Two faults did cross each other at the location of the borehole, providing the necessary flow of water. Dr. Haukur Jóhannesson decided the exact location of the drilling site. Both faults did fit into the convection cell formula, and therefore the site was considered more convincing. Knowledge is to be utilized!

I feel like we underestimate the importance of the Reykjanes Ridge when dealing with the geology of Iceland. Look at that big feature! Most important is found above the convection rolls!

The basics of the Reykjanes Ridge can be described in a very simple way. To make it clear, let us have a look at this drawing of convection rolls with a Google map with division lines added:

The SW corner of Iceland can be seen. The Reykjanes Ridge ends there. Instead volcanic systems are found en echelon along the Reykjanes Peninsula.

The Reykjanes Ridge is the most typical feature to begin studying the convection cell system. Two convection rolls, forming one pair of upwelling, creating a distinct feature of a Mid Ocean Ridge. The alignment of the ridge fits perfectly to the calculations made according to the Coriolis Force acting on mantle material flowing slowly under perfectly balanced conditions.

Compare in Google maps Hekla and its counterpart 30° to the East. Why? Because the same convection cell pattern is found under the tectonic plates at 30° interval on the same latitude. Find the correct spot in Norway and compare to Hekla. The pictures look strikingly similar! Still, Norway is geologically not similar to Iceland at all. How can this be?

Hekla and Trondheim area – 30° of longitude apart compared

All this can easily be explained. So join the club!

There are layers of convection cells under Iceland, influencing the crust and surface above. One of the few things I have anticipated publicly according to this grid was the finding of abundant geothermal source in Eyjafjördur near Akureyri. The lines of the grid intersect each other where a tunnel was made through the highland of Vaðlaheiði. Not many took it seriously at the time, but I pointed out that the area close to Akureyri is the counterpart of the Krafla volcanic site about 1.5° of longitude to the East, (each convection cell spans 1.5° from East to West). The fundamental difference is the fact that Krafla is within a volcanic rift zone, but Eyjafjördur region is not. Therefore the effect of the convection layer hub underneath only creates moderate geothermal activity in Eyjafjörður, (or low temperature area).

Here is a map for explanation 🙂

The South Iceland Seismic Zone is aligned E-W across the Southern Lowlands. The earthquake faults have N-S direction. So why is that? It can be easily explained according to the framework of mantle convection cells between the edge of the Western Volcanic Zone on one hand and the edge of the Eastern Volcanic Zone on the other. This leads to the fact you can almost use the system of faults as a compass!  As convection takes place 120 km below the surface, the regularity found within the top 10 km of brittle crust is just amazing. The South Iceland Seismic Zone is one of the clearest manifestations of the mantle current system within the Earth.