Magma surge towards the surface would be very powerful

The current situation at Bárðarbunga is many times more powerful than the one that led to the Gjálpar eruption in 1996. Several hundred earthquakes were detected back then, but today they're already in the thousands. Scientists interpret this as a massive magma movement that may quickly surge towards the surface.

Kristín Vogfjörð, research director at the Icelandic Meteorological Office, says that the current seismic activity at Bárðarbunga is many times more powerful than any on record for the site.

"It's very powerful," she says. For comparison she notes that thousands of quakes have been measured at Bárðarbunga in the past week, but in the Gjálpar eruption in 1996 they were only a few hundred.

The activity is interpreted as magma moving up under the Bárðarbunga caldera, then moving into an underground chamber to the northeast, under the Dyngjujökull glacier. It's possible that the magma stops there and never reaches the surface.

"That's a possibility - if the chamber can hold all the magma," says Kristín. She says that GPS readings suggest that the pressure is stable while the magma moves away from Bárðarbunga into this chamber.

"While this is going on, it may never reach the surface. But we still need to keep an eye on it because the volume of magma is incredible," she adds.

There are still no signs that the magma is heading for the surface. Kristín says that it's still at a depth of 5-10 kilometers.

"There is no indication that it's moving further up than that. But if it were to happen, it would happen very quickly," Kristín states.