TerraSAR-X image shows spread of lava at Bardarbunga

The lava outflow on the Holuhraun field northeast of Iceland's Bardarbunga volcano continues unabated. 

The lava field has grown to cover an area greater than 25 square kilometres. 

In this satellite image, the extent of the lava field is revealed using different colours.

To create this image, three sets of data were acquired at different times, but from the same viewpoint, and then superimposed.

They date from 13 August, 4 September and 15 September 2014 and were acquired by the German radar satellite TerraSAR-X.

Yellow shows the growth of the lava field between 13 August and 4 September; red shows the expansion between 4 and 15 September.

It is obvious that the area has doubled. A second eruption area can also be seen as a small red spot in the lower right corner of the image.

Researchers at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Remote Sensing Technology Institute (Institut für Methodik der Fernerkundung; IMF) are continuing to monitor the area.

Radar images can be used to analyse changes to Earth's surface throughout the entire process.

The DLR Earth Observation Center also measures the emissions of sulphur dioxide on a daily basis.

Bardarbunga sulphur dioxide cloud

Iceland raises its volcano aviation warning alert to RED

Iceland's authorities have raised the aviation warning code for a region close to the subglacial Bardarbunga volcano after a small fissure eruption in the area.

No volcanic ash has been detected, however, and the Civil Protection Department said all Icelandic airports remained open.

The country's meteorological agency said scientists were monitoring the eruption in the Holuhraun lava field, about three miles north of the Dyngjujoekull glacier.

"Visual observation confirms it is calm, but continuous," the weather agency said on its website.

This morning's eruption at about 0600 BST followed a smaller one in the same site on Friday that also prompted authorities to briefly raise the aviation warning code to restrict flights in the area.

Thousands of small earthquakes have rocked the region in recent days, leading to concerns that the main volcano may erupt.

The red warning code, the highest in the country's alert system - meant that no flights are allowed in an airspace area of about 40 square nautical miles north of the fissure eruption area, up to 6,000 feet (1.1 miles) from the ground.

Aviation officials said the restrictions do not affect commercial flights, which fly much higher than that.

Authorities said lava fountains of about 165ft (50m) high erupted from the fissure, estimated to be almost a mile long.

The fissure eruption appeared about 28 miles from the main Bardarbunga volcano, which lies under the vast Vatnajokull glacier that dominates the eastern corner of Iceland.

Though remote and sparsely populated, the area is popular with hikers in the summer. Officials earlier evacuated all tourists in the region after intense seismic activity there.

Although today's fissure eruption was more powerful than the one on Friday, experts say the situation is contained and is unlikely to result in the same level of aviation chaos as 2010.

Iceland Rocked by Thousands of intense earthquakes

This is a Saturday May 8 2010 file image taken from video of a column of ash rising from Iceland's Eyjafjallajokul volcano. 

It was reported Tueday Aug. 19, 2014 that thousands of small intense earthquakes are rocking Iceland amid concerns that one of the country's volcanoes may be close to erupting. 

Iceland has raised its aviation alert level for the risk of a possible volcanic eruption to orange, the second-most severe level. 

The alert is worrisome because of the chaos that followed the April 2010 eruption of Eyjafjallajokul, when more than 100,000 flights were cancelled because volcanic ash floating in the atmosphere is considered an aviation safety hazard. 

Credit: AP Photo/ APTN

Thousands of small intense earthquakes are rocking Iceland amid concerns that one of the country's volcanoes may be close to erupting.

Iceland has raised its aviation alert level for the risk of a possible volcanic eruption to orange—the second-most severe level.

The alert is worrisome because of the chaos that followed the April 2010 eruption of Eyjafjallajokul, when more than 100,000 flights were cancelled because volcanic ash floating in the atmosphere is considered an aviation safety hazard.

Some 3,000 earthquakes have taken place since Saturday in Bárðarbunga (pronounced [b'aurðarbuŋka]), a subglacial stratovolcano located under Iceland's largest glacier.

Iceland's Meteorological Office said that no earthquakes above magnitude 3 have been recorded in the last 24 hours.

Seismologists said Tuesday magma is moving, but it is traveling horizontally.