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There is a reason for the square shape of the Iberian Peninsula. The northern and southern coasts were originally both cut E-W by transform faults of the Atlantic, extending from the mid-ocean ridge. Those structures clearly trend to form along the main directions of east and west, due to Earth’s rotational effect on the underlying mantle. Similarly, the west coast is aligned directly N-S, and in general the Mid-Atlantic Ridge is undisputably, as a large-scale feature, aligned N-S, although swaying back and forth. For orientation, you can watch: https://www.youtube.com/watch?v=-ye-3WGFh_Y

The result is a square shaped area, and the origin of that shape should be analysed in some detail. Here, it is explained according to the convection rolls system underneath. First, we should look at the peninsula in a clear way:

Then let us insert the relevant lines, the square itself and the convection rolls two layers pattern:

We are so used to looking at maps, that the special shape somehow escapes from our attention, but drawing the square it can not be denied that it follows the E-W and N-S alignments very closely, and would be statistically unimaginable as a coincidence. This can be explained, providing an opportunity to enjoy this geological aspect of the area.

The Wikipedia article about the Iberian Peninsula: https://en.wikipedia.org/wiki/Geology_of_the_Iberian_Peninsula

There is a clear difference between subduction zones facing east (slope 27.1°) and west (slope 65.6°), on the average. The first reason to be examined is Earth’s rotation. Slab is subducted about 660 km, close to 1/10 of Earth’s radius, and therefore it loses rotational velocity on the way. As this happens very slowly, it might be overlooked, but this is actually what happens. All this mass loses considerable amount of kinetic energy to the environment during the process. This fact constantly alters the slab dip as it descends into the mantle. It occurs linearly, having rotational speed u=1 at the surface, and u=0.9 close to the depth of 660 km. The Earth’s radius is 6,370 km, and therefore we roughly say that when fully subducted it has lost 10% of original rotational velocity.

This is shown here with the drawings below. Two rather similar triangles appear, as it is supposed that the lithosphere plates subducted westwards and easwards are affected equally by the difference of rotational speed, only with opposite signs of plus and minus. The distance gap is shown with the short line of the triangle, connecting the red line of real flow, and the black lines of imaginary trend of no rotation. Those lines are found to be accurately in between 65.6 and 27.1, or about 46°.

The information about average dip of slab is from the article ´Polarized Plate Tectonics´ (2015), by Carlo Doglioni and Giuliano Panzax.

The earthquakes make people wonder – what is going on there? The location is outside the West Volcanic Zone and is by some regarded as intra-plate seismic activity.

This is a geothermal area, just south of the most powerful low temperature geothermal are in Iceland. Some large earthquakes occurred there in 1974 https://timarit.is/page/1453203#page/n0/mode/2up. According to the model considered here, with convection rolls found underneath, these earthquakes can be explained differently.

The location of epicenter can be compared with the West Volcanic Zone (WVZ), which closely resembles the East Volcanic Zone (EVZ) in many ways. The eastern margins of the WVZ and the EVZ are oriented in the same way, but the western margins differ.

As the southern half of the WVZ is here regarded as a square, the N-S axis is vulnerable to shearing. The red lines west of the epicenter extend from the Reykjanes Ridge, and are supposed to be the up-welling division line between two convection rolls at the depth of 120 km, and another pair of convection rolls farther down, also up-welling. This causes tension, because the local convection rolls (in between red and blue lines) oppose the main drift of the North American Tectonic Plate, causing rifting. This causes earthquakes in the area, even though it is outside the WVZ as detected from the surface.

The Yellowstone Caldera is not alone. Many older remains of similar calderas can be found arranged in a row west of the presently active one. But there is something more about it.

Besides the calderas, fissure svarms and the Nevada Rift Zone are found north and south of the track. https://www.usgs.gov/observatories/yvo/news/just-how-long-has-yellowstone-hotspot-been-around?qt-news_science_products=4. These extra volcanic features are about 17 million years old, and show resemblance with the convection rolls presumed to be found underneath. The convection rolls theory can also explain the long features associated with the caldera. In Iceland, there are many volcanic systems combined of a caldera with fissures extending from it to the north and south. Another analogy is the fact that the Emeror Chain, considered to be a part of the Havaii Chain, actually formed along a north-south aligned line, with volcanic activity propagating south until it reached the latitude of the present Hawaii hotspot. Therefore, the hot spots, such as Yellowstone and Hawaii, are actually short sections of ´hot lines´, extending secretly north and south of them, underneath the tectonic plates.

This year, 2021, it became the hobby of many people to climb the vicinity of Fagradalsfjall to watch the eruption of Geldingadalir on Reykjanes Peninsula of SW Iceland. Then, for three months, no lava was detected flowing from the craters, and we officially claimed that the event was over. (https://www.ruv.is/frett/2021/12/18/gosinu-lokid-en-afram-kvikusofnun-vid-fagradalsfjall?term=goslok&rtype=news&slot=6) Three days later, similar earthquakes started as preceded the eruption in March. As I have my own model to scrutinize the ongoing, there are a few things to be noted:

1. The dike keeps un-solidified in the dike for a rather long time after the eruption has stopped. A possible explanation is continuous flow taking place within it. The flow must have traceable beginning and end point. According to my logic, for those three months of quiescence, magma has been flowing smoothly into the dike from the NE, and out of it at the SW end. If nothing like this would have occurred, the relatively thin dike should have solidified.
2. The volume of lava already on the surface can be compared with some facts we know about its origin. (A) With petrological methods it has been found out that it has been melted at the depth of 14-16 km. It gives us the height of the melt zone of 2,000 -3,000 meters from the lowest to the highest level. (B) During the half a year, or so, the first chapter of the eruption lasted, 150,000,000 cubic meters of lava flowed on the surface.
3. We know that no indication is available about the real source of the magma. We know about the influx into the dike NE of the eruption site. We can not trace any magma chamber, no original inflow, no lowering at a place where magma might be flowing out to somewhere. We only notice that magma has been flowing into the dike and the related changes of its surroundings. These transactions take place within the ductile crust below Moho, where the flow can not be measured directly.
4. I would add a guess, according to my model, that the source of magma is found within the central axis of the Mid-Atlantic Ridge. That axis is actually the division line of two convection rolls, rolling opposite to each other, causing upwelling of magma along the entire Reykjanes Ridge. The line of division can be traced farther than the Reykjanes Ridge itself, and the perpendicular line from the eruption site and the relevant dike is 23 km long, or 23,000 meters.
5. We therefore have some information available. a) V=150,000,000 km3, b) h=3,000 m, L=23,000 m. We can the calculate that dike-like melting volume, within the ductile part ot the depth level between 14-16 km, 23 km long, would be about 2 meters wide.
6. Considering that not all magma should find its way to the surface, but maybe half of it, the deep-dike width should be about 4 meters. Moreover, the heat source is ascending molten rock, not finding its way to the surface.
7. The first melt has accounted for the first chapter of the eruption, but the heat source seems to be still actively adding to the melting process. If the eruption starts again, the petrological difference, evolving over time, could therefore indicate where the real source of magma is found.

This is one way in which we can explain the absence of measureable indications of the origin of magma, providing lava for the Reykjanes Eruption. In Iceland, the name is Geldingadalir Eruption, according to the area where the craters are found. The Geldingadalir valleys are at the side of Fagradalsfjall, a mountain of Reykjanes Peninsula.

A system of earthquake faults is traceable over the peninsula, and the mountain Fagradalsfjall. The eruption takes place through one of those earthquake faults, with N-S orientation at depth, but NE-SW trend at the top. The NE-SW aligned dike does cros the N-S fault at the side of the mountain, and there the eruption takes place. The system of earthquake faults does sway from the E-W oriented South Iceland Seismic Zone over the peninsula, only to become adjacent with the Reykjanes Ridge. As the faults become filled with additional lava, gravity anomalies develop as a result. This is a likely explanation why the so-called V-shaped ridges form semi-parallel to the Reykjanes Ridge. Those are not real ridges, but gravity anomalies due to this additional mantle material which has consolidated within the crust.

For basic orientation, I add this map:

Hopefully, we can use this opportunity to learn more about the basics of this structure underneath, leading to volcanic eruptions, earthquakes and formation of geothermal areas.