Geologists focus on one volcanic zone of North Iceland, the one extending from Askja to Öxarfjörður. The Skagafjörður volcanic zone is still active, as earthquakes occasionally show, and Hofsjökull might be a part of it still active. Again, we can compare model and real circumstances:
The accurate consistency between model and surface features is one more reason that the convection rolls of the model are correctly calculated.
To learn about Skagafjörður volcanic zone, please read https://www.google.com/search?ei=XydrXKKQJcnawALJx6rwDA&q=%C3%A1rni+hjartarson+skagafj%C3%B6r%C3%B0ur&oq=%C3%A1rni+hjartarson+skagafj%C3%B6r%C3%B0ur&gs_l=psy-ab.3…4355.9971..11309…0.0..1.210.2360.16j6j1……0….1..gws-wiz…….33i21j33i160j0i22i30.HD99sOGAOXQ