The North Volcanic Zone is differs from the WVZ and EVZ in the south. It is aligned directly NS as a whole, but individual volcanic systems point slightly to the NE. Comparing the grid to the map of National Land Survey of Iceland gives this picture:
The vectors of tectonic drift as mesures for ISNET 2004 are divided aroun that NS oriented NVZ. By coloring the main polygons of the zone red, the main volcanic areasare seen to be found within them, thereby functioning to meet the tectonic drift as these polygons break up, making space for more magma input from below.
The directional effect on tectonics resulting from diverging on the polygons is thereby quite obvious.