A tremendous gush of lava in Iceland that began six weeks ago shows no signs of slowing. The eruption, on a plain of old lava called Holuhraun in the Bárðarbunga volcanic system, has spewed out enough molten rock so far to fill 740 Empire State buildings and has buried, on average, an area the size of an NFL football field every 5.5 minutes.

At this rate, the lava flow will soon be larger than any seen for more than two centuries in the volcanically active island nation. And there's no telling when it will stop—months, maybe, or years.

"It's amazing that it has gone on at this rate for so long," says volcanologist John Stevenson of the University of Edinburgh. (See "Icelandic Volcano Rumbles Raise Eruption Fears.")

No one lives near the growing lava flow. But continuing earthquakes associated with the eruption suggest that a separate eruption is possible. If new lava emerges under the nearby ice cap, the meeting of fire and ice could unleash massive floods and belch out a cloud of steam-driven ash similar to the plume that disrupted air travel during the 2010 eruption of Eyjafjallajökull. (See "Q&A: Why Iceland's Volcanoes Have Vexed Humans for Centuries.")

Despite its remoteness, the Holuhraun eruption is one of the best monitored in history, thanks to new instruments deployed by the European Commission-funded FUTUREVOLC project and other international teams. (Go behind the scenes of filming the volcano in "The Logistical Nightmare of Visiting a Volcano.")

Scientists hope lessons learned at Holuhraun will also help them understand the formation of ocean floors, which, like Iceland's eruptions, takes place at geological seams where tectonic plates tear apart from each other.

"We have a lot, a lot of data, so much data that we can really see how the eruption is evolving," says FUTUREVOLC member Stéphanie Dumont, a geophysicist at the University of Iceland's Institute of Earth Sciences. A network of seismometers, for instance, helped scientists track the rock-splitting movements of the subterranean magma now feeding the eruption.

At first a shallow underground chamber was thought to be the source of the magma beneath this Bárðarbunga eruption. But the longer the lava continues to flow, the more likely a deeper reservoir is involved, says volcanologist Agust Gudmundsson of Royal Holloway, University of London. "We do not know of any volcano in the world where you can tap a shallow chamber and it keeps open this long."

There's no telling when the spigot to the depths will turn off, so there may be a lot more lava to come and a lot more sulfur dioxide, a toxic gas released by the eruption that can drift long distances. (See "Iceland Volcano Spews Giant Ash Clouds.")