Hekla, Grímsvötn, Bárðarbunga and Katla are all preparing for eruption. mbl.is/Ómar Óskarsson

According to geophysicist Páll Einarsson, four of Iceland's volcanoes are showing increased amounts of activity in preparation for another eruption.

Katla is the most active that it's ever been in four decades. "Katla has been unrestful since this autumn."

The other volcanoes showing increased activity are Hekla, Grímsvötn and Bárðarbunga.