The Tjörnes Fracture Zone combines the North Volcanic Zone with the Kolbeinsey Ridge. The alignment of epicenters follows the mathematical model of convection rolls closely. Today, the ‘Met Office’ map looked like that:
Comparing with the convection rolls model shows how the SE-NW alignment follows the division line, whereas the N-S aligment does trace the central axis of the polygon marking the very beginning of Kolbeinsey Ridge.
Besides that, Grímsey is pointed out. Grímsey Island is the northern most inhabited part of Iceland. It is found close to a ‘hub’ of division lines of different layers, leading to an anomaly of volcanic and geothermal activity within the surrounding area.