It is now accepted that the two eruptions of Fagradalsfjall in 2021 and 2022 took place where an active dike crossed NS oriented earthquake faults.
Several NS earthquake faults have been mapped, and it turns out that the interval between them is quite regular. Therefore, by extrapolating the mapped part of the earthquake zone, the position of other earthquake faults can be guessed theoretically, as shown here below. Thick NS oriented lines show the already mapped faults, and thinner blue lines show the theoretical ones, numbered 1-8, along with the nineth which is theoretically connected with Keilir volcano. (The locations of those lines are not meant to be exact, only indicative according to the so-called bookshelf theory of parallel eartquake faults. See for instance: https://opinvisindi.is/bitstream/handle/20.500.11815/4328/Einarsson_2008.pdf?sequence=1&isAllowed=y.)
The drawing is superimposed on a map from the Icelandic Met Office, plotting recent earthquakes in the area. The dike covers the intervals of 8 or 9 earthquake faults, and if an eruption occurs within the area, the magma should make use of the weakness caused by one of those earthquake faults to reach the surface.
The map inserted, with mapped earthquake NS faults, is from the essay written by Vigfús Eyjólfsson and Páll Einarsson: https://www.mbl.is/media/36/11536.pdf. Earthquake faults mapped by Sigurlaug Hjaltadóttir and Kristín S. Vogfjörð are also added within that map: (https://www.vedur.is/media/vedurstofan/utgafa/greinargerdir/2006/06001.pdf).
Magic Magma 