Eruption in Bardarbunga's main caldera is now considered one of four likely future scenarios, scientists stated Saturday morning. Intensive seismic activity continues, with a 5.4 magnitude earthquake hitting the volcano's south rim at 7:03 GMT.
Friday's eruption "a geological accident"
A small fissure eruption, which started in the early hours of Friday, was short-lived, lasting only 3-4 hours. The eruption was located at Holuhraun, an ice-free area north of the subglacial volcano. Scientists even describe the tiny event as a "geological accident", pointing out that the lava which entered the surface was only about a thousandth of the magma on the move under the surface.
Last week's eruption failed to break through ice
Scientists have now concluded that another small eruption, albeit ten times bigger than the one on Friday, took place on Saturday, 23 August, in the southeastern slopes of Bardarbunga, but failed to break through the 400-600 m (1300-200 ft) thick glacier above. Several depressions, 10-15 m deep (30-50 ft), were spotted during a reconnsaissance flight on Thursday, and are thought to be a consequence of the eruption causing the ice to melt.
Eruption at Bardarbunga added to list of likely scenarios
After an official meeting Saturday morning, scientists stated that it was unclear how the situation would develop. According to the statement, four scenarios are considered most likely:
Gradual reduction in seismic activity, with no further eruptions.
Another eruption in an ice-free area north of the glacier, possibly on a new fissure. Such an eruption could include lava flow and explosive activity.
An eruption, partly or wholly subglacial, outside the main caldera, near the northern edge of the glacier. This would most likely cause flooding to the north, feeding into the river Jokulsa a Fjollum. This scenario might include explosive, ash-producing activity.
An eruption at Bardarbunga. The eruption could cause an outburst flood and possibly explosive, ash-producing activity. In the event of a subglacial eruption, the flood would most likely feed into Jokulsa a Fjollum. However, it is not possible to exclude other paths, to the north or to the south.
5.4 earthquake at the volcano's rim
Seismic activity in the area continued Saturday, with around 700 earthquakes detected from midnight to noon. The largest quake was a magnitude 5.4 on the main caldera's south rim. Two additional quakes above magnitude 4 were detected on the volcano's north rim.
The two week, non-stop seismic activity is the most intensive on record in this area. It is caused by a dike intrusion (hundreds of millions of cubic meters of magma) migrating north from the volcano, underneath the surface.
Evacuation orders remain in effect in an extensive area north of the glacier. The area has no permanent inhabitants, but the evacuation includes parts of Vatnajokull National Park, with popular tourist attractions like Askja, Herdubreidarlindir, Hvannalindir and Kverkfjoll remaining closed.
Bardarbunga is one of Iceland's most hazardous volcanoes, and earthquakes in the same area triggered a subglacial eruption in 1996, leading to massive flooding to the south. The last major eruption at Bardarbunga was in the 19th century.