A subglacial eruption is underway at the Bardarbunga volcano in Iceland, which has been the subject of a number of alerts after being rattled by thousands of earthquakes over the past week.

Iceland has issued a red alert to the aviation industry for the Bardarbunga volcano, meaning significant ash emissions are likely, and the Icelandic Met Office has given warning about the subglacial eruption, which has been categorized as "minor" at this point.

The red alert is the highest warning on the country's five-point scale, and the air space over the site has been closed, but all Icelandic airports currently remain open, according to authorities.

Iceland's Eyjafjallajokull volcano erupted in 2010, producing an ash cloud that severely disrupted air travel.

Seismic data indicates that lava from the volcano is melting ice beneath the Vatnajokull glacier, according to Vulcanologist Melissa Pfeiffer, who spoke to the AP. She said it was not clear when -- or if -- the eruption would melt the ice and send steam and ash into the air, but authorities are not taking any chances, given the magnitude of the possible complications from such an event.

Iceland has also put the Coast Guard on alert after the Met Office warned that the volcano, one of the country's biggest, is showing increased levels of activity.

“The rate of earthquakes has increased such that they are happening so quickly that it is difficult for the seismologist to discern individual events,” the Reykjavik-based agency said in a statement on its website. “The activity continues and an eruption can therefore not be ruled out.”

Authorities evacuated several hundred people from the highlands north of the glacier as a precaution earlier this week. The area is uninhabited by residents, but is popular with nature-lovers and hikers.

Iceland sits on a volcanic hot spot in the Atlantic's mid-oceanic ridge and eruptions have occurred frequently, triggered when the Earth's plates move and when magma from deep underground pushes its way to the surface.

The Bardarbunga volcano is 15.5 miles wide and rises about 6,234 feet above sea level, and last erupted in 1996.

Roads to and from the area have been closed and the Coast Guard was today scheduled to fly over the area with scientists from the University of Iceland and people from the Civil Protection Agency, according to Bloomberg.

A 2010 eruption of another Icelandic volcano, the Eyjafjallajokul volcano, produced an ash cloud that caused a week of international aviation chaos, and caused more than 100,000 flights to be cancelled. 

Pfeffer said the amount of ash produced would depend on the thickness of the ice, according to the AP.

"The thicker the ice, the more water there is, the more explosive it will be and the more ash-rich the eruption will be," she said.