Pair of Quakes Rattle Iceland Volcano Aviation alert issued after 5.1, 5.3 earthquakes By Newser Editors and Wire Services Posted Aug 24, 2014 4:31 AM CDT 4 comments Comments In an image from an Aug. 19, 2014 video, a sign is posted on the road next to Bardarbunga, a subglacial stratovolcano located under Iceland's largest glacier. (Uncredited) (Newser) – Two earthquakes measuring over 5 in magnitude—the biggest yet—shook Iceland's Bardarbunga volcano today after the country issued an aviation red alert warning that an ash-emitting eruption may be imminent. Iceland's Meteorological Office recorded earthquakes of 5.3 and 5.1 in the early hours. It said there were no signs of an eruption. The volcano, underneath Iceland's vast Vatnajokull glacier, has been rattled by thousands of small earthquakes over the past week. Yesterday scientists reported a small eruption under the ice, but it was not visible on the surface, and the Met Office later said it appeared to have stopped. Authorities have declared a no-fly zone of 100 nautical miles by 140 nautical miles around the epicenter as a precaution. A 2010 eruption of Iceland's Eyjafjallajokul volcano caused a week of international aviation chaos, with more than 100,000 flights cancelled. Any new eruption is likely to be less disruptive. European aviation authorities have changed their policy, giving airlines detailed information about the location and density of ash clouds but leaving decisions to airlines and national regulators. Britain's National Air Traffic Service said it was monitoring what it called a "dynamic situation" but was expecting normal operations today. Virgin Atlantic said a London-to-San Francisco flight took a slight detour yesterday to avoid Iceland's no-fly zone.