Loki-Fögrufjöll

The Loki-Fögrufjöll ( volcanic system; also known as Hamarinn after its central volcano or Lokahryggur ) is a subglacial volcano under the Vatnajökull glacier.

The subglacial volcano is found within the Bárðarbunga fissure volcanic system, but is outside the caldera of Bárðarbunga itself. Earthquake swarms associated with the volcano are separate in time and place from other swarms in the Bárðarbunga system. The fissure swarm extending south-west towards Torfajökull has not had recent earthquakes or erupted in the Holocene. A geothermally and seismically active ridge called Lokahryggur or the Loki Ridge, extends eastward from Hamarinn under the ice to where in 1996 the Gjálp volcanic fissure erupted between Bárðarbunga and Grímsvötn and produced a large jökulhlaup.

The last confirmed eruption was in 1910 when tephra was erupted, but the system may also have had subglacial eruptions in 1986, 1991, 2006, 2008 and 2011.