The Gjálp fissure vent eruption in 1996 revealed that an interaction may exist between Bárðarbunga and Grímsvötn. A strong earthquake in Bárðarbunga, about 5 on the Richter scale, is believed to have started the eruption in Gjálp. On the other hand, because of the magma erupted showed strong connections to the Grímsvötn Volcanic System acc. to petrology studies, the 1996 as well as a former eruption there in the 1930s are thought to have taken place within Grímsvötn Volcanic system.