Some heavy earthquakes (M5+) had taken place in the central volcano Bárðarbunga before and proved to be precursors of the eruptive events. New seismological studies (2019) see a parallel to the 2014-2015 eruptions and to the caldera drop in Bárðarbunga central volcano and postulate a similar magma migration to the eruption site though on a smaller scale. This could mean that the volcano is part of the fissure system of Bárðarbunga, not Grímsvötn.