The conclusions of these studies can be arranged in a model of the geothermal system which shows the flow of boiling water from under Hengill along Kyrdalshryggur on to Nesjavellir. Between Kyrdalshryggur and Koldulaugagil geothermal energy is found at a depth of one kilometer, but at a greater depth the temperature is highest in the Kyrdalshryggur. At still greater depths the geothermal system extends beneath Nesjavellir and Kyrdalur. Palagonite turf predominates in the upper five hundred melees of rock, and there is basalt beneath them. Magmatic intrusions become more common at greater depths and become the predominant rock type at a depth of 1,400-1,600 meters and below.
Reservoirs often occur at the peripheries of intrusions, especially from intermediate acid rock.
There is a fault at the Kyrdalshryggur which is indiscernible at the surface, although the wells clearly show that the valley floor has subsided.