Another possibility is that Bárðarbunga magma entered in a smaller portion the magmatic system of Grímsvötn and started the eruption by this intrusion. Bárðarbunga is known for such tendencies, her magma mingled with Torfajökull magma at least three times in the past which resulted in bimodal eruptions, eg. of the Veiðivötn and at Landmannalaugar by the end of the 15th century.