Thanks for the update. You know what I did...I pulled up [link to hisz.rsoe.hu] and I looked at the islands. If you zoom in on Hierro you will see what look like sink holes or elevation changes showing destabilization and deformation near the crest lines. The place is full of cuts and breaks and cliffs. I don't know how old or new those deformations are BUT they're there. If someone has google earth they may be able to get a newer view of the place.