Geologists in Iceland are warning that Öræfajökull volcano may be getting ready to erupt.
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The volcano has been showing increased signs of activity, with a new half-mile caldera forming just last week, according to the Icelandic Meteorological Office. This comes on top of elevated seismic activity in the area in recent months.
The meteorological office issued a yellow alert for aviation on Friday, indicating the volcano should be closely watched.
“There is considerable uncertainty about how the situation will evolve,” the Met Office said today.
Öræfajökull, an ice-covered volcano located in Vatnajökull National Park in southeast Iceland, last erupted in 1727 and is the country's largest active volcano. Before that, the volcano erupted in 1362.
ABC News' Kirit Radia contributed to this report.