Katla is a mystery, because no one has seen the volcano. Now we can detect it easily with modern technology through the ice sheet of Mýrdalsjökull, but somehow it remains obscure.
The division lines between convection rolls crossing below the mountain are marked on the map below. The black line is a downwelling line of the upper most layer, and the red line is upwelling line of the second layer.
Many of the most famous active areas in Iceland are found along these lines. That is in accordance with the activity of Katla – surprising everyone each time it erupts.
