Extending the Reykjanes Ridge, a symmetric picture of Iceland emerges. This is consistent with the presumption that the two convection rolls shaping the Reykjanes Ridge extend under Iceland in the way as drawn with red line across Iceland from SW to NE.
The Icelandic platform forms an ellipse around the extension, aligned E-W. The two volcanoes of Hekla and Eyjafjallajökull are on the NS axis of the ellipse. The two outposts of Icelandic volcanoes, Snæfellsjökull and Snæfell, are equadistant from the NS axis, and located exactly on the same latitude. If the Kolbeinsey Ridge is also extended, it is found reaching the same central point, merging with the NS axis of the ellipse and the volcanoes Hekla and Eyjafjallajökull. This high degree of consistency is in conformity with the analysis of the convection rolls below Iceland.
A map showing volcanic zones, for comparing with the drawing on Google Earth picture shown above.