A row of newly formed cauldrons (depressions) was spotted in the Vatnajokull glacier near the Bardarbunga volcano during a reconnaissance flight today, leading to speculation that a small eruption had begun there. Scientists estimate that 30 - 40 million cubic metres of ice have been melted.
According to a statement from the Icelandic Civil Protection Agency (CPA) early Thursday morning, three cauldrons were seen, 4 - 6 km long, 1 km wide, with a depth of 10 - 15 metres, near the southeastern rim of the Bardarbunga caldera. They are not believed to be associated with the intrusion that has been propagating to the north in recent days.
Magnus Tumi Gudmundsson, professor of geophysics at the University of Iceland´s Institute of Earth Sciences, estimated in an exclusive interview with RUV that the subglacial activity had melted 30 - 40 million cubic metres of water beneath the cauldrons. In this location, the glacial ice is hundreds of metres thick.
As the cauldrons are at a location on the watershed line between the northwestern and the southern part of Vatnajokull, there are indications that the meltwater has flowed to the nearby reservoir at Grimsvotn (another active volcanic site in Vatnajokull), about 20 km away. "But there is a large degree of uncertainty in all this, and until we fly again tomorrow over the area, it is very difficult to say something substantive about this," he added. "Circumstances at the glacier today were not favourable and we can not exclude that more cauldrons have been formed,“ Gudmundsson said. "We will hopefully know more after the reconnaissance flight tomorrow morning."
Earthquake monitoring has not revealed any signs of volcanic tremor in the area where the cauldrons were found, and there are no indications that a large eruption is underway. Monitoring of nearby glacial rivers has not shown any increase in volume or conductivity (usually a sure sign of magma-water interaction).
Cauldrons like the ones seen today are usually formed by a subglacial eruption or geothermal activity in the bedrock under the glacier.
Strong seismic activity has been detected in the area around Bardarbunga caldera since Aug. 16, with magma flowing out of the caldera to a dike intrusion propagating to the north and east of Bardarbunga. That activity is still ongoing.
Volcanic eruptions are frequent in Iceland, though they seldom cause harm to humans. The last volcanic eruption in Iceland was in 2011, when Grimsvotn, another subglacial volcano, spew a plume of ash 12 km (7 mi) into the air, leading to the cancellation of hundreds of flights internationally. A more notable eruption occured in the spring of 2010, at Eyjafjallajokull volcano, causing a major disruption of European and transatlantic flights.