Over 400 meter (1312 feet) wide holes have formed in Vatnajökull, Iceland's largest glacier. RÚV reports. This is near the Bárðarbunga area, which had a volcanic eruption between 2014 and 2015.
According to geologist Magnús Tumi Guðmundsson, the entire Bárðabunga landscape changed after the eruption, with increased geothermal heat that has melted away a hundred meters of thick, glacial ice, forming these calderas.
In fact, this marks the first time in hundreds or even thousands of years that the ground beneath the glacier can be seen. Magnús Tumi warns that this increases the chances of a glacial outburst flood, although nothing can be confirmed as of yet.
Seismic activity in Bárðarbunga has been high for the past years, due to its last eruption. Magnús Tumi says the area needs to be carefully watched in order to watch out for any more calderas that might trigger a glacial outburst flood.