[5] There are high temperature geothermal areas associated with the Hofsjökull central volcano, its northern fissure swarm, and Kerlingarfjöll to its south.

[11] The Hofsjökull central volcano caldera is located under the south-west portion of the icecap and is 6–7 km (3.7–4.3 mi) wide and about 600 m (2,000 ft) deep.

[3] There are post ice–age lava flows to the south, east and north of the Hofsjökull central volcano.

[12] In the case of Kerlingarfjöll which is not covered by 600 m (2,000 ft) of ice, the rhyolite is found close to the two central caldera.

[16] The fissure swarms and a radial pattern of dike intrusions appear to radiate away from the Hofsjökull central volcano suggesting that it is a significant local stress field.

[17] To the south the 6 km (3.7 mi) wide western part of the fissure swarm has multiple mainly mostly tensional faults orientated at 30° that are traceable as they extend across the Langjökull volcanic system's 10,000 years ago origin Kjalhraun lava shield.

This implies by geometry that the relative plate velocity across this region is small which geologists usually predict means little seismic or volcanic activity.