The area called Marteinsflaeda is north of Lakes Gaesavotn, and the 4wd track there continues to Valley Bardardalur.  It is divided into the Southern and Outer Hot Springs.  The southern thermal area yields more water, 30-40°C hot, which appears through a narrow crack on the surface.  A few decades ago it was dynamited and a nice bathing pool was the result.  The outher thermal area is located at the western edge of the Laufrond Lava Field, the main breeding area of the Snowy Owl in Iceland.