Thousands of small earthquakes have rattled Iceland's Bardarbunga volcano over the last five days, prompting meteorologists to warn of an increasing risk of eruption and causing public safety authorities to evacuate tourists from the popular summer climbing venue.
The escalating seismic activity on the volcano has also led authorities to issue an aviation alert for possible ash releases that could interfere with navigation.
In April 2010, the smaller Eyjafjallajokull volcano spewed ash nine miles high, sending a particle cloud over much of Europe that grounded 100,000 flights and 8 million travelers for a week because of the potential damage to aircraft engines.
At least 3,600 temblors have pulsated deep beneath the glacier-capped Bardarbunga volcano since Saturday, including a magnitude 4.5 quake on Monday that was the strongest in the area since 1996, the Icelandic Meteorological Office reported.
The rash of quakes and detected movement of magma within six miles of the volcano's surface "implies increased potential of a volcanic eruption," the meteorological office said in its Wednesday update.
Authorities raised the eruption threat level to orange, the second-highest on the five-level scale, indicating "escalating unrest with increased potential of eruption," the weather office reported.
Iceland's Civil Protection Department reported Wednesday that it had evacuated more than 300 people, mostly foreign visitors, from the hiking and climbing areas north of the Vatnajokull glacier. Roads leading into the unpopulated recreation area have also been closed as a precaution against outdoor adventurers becoming trapped there in the event of an eruption.
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