More than 130 earthquakes were reported across Iceland on Tuesday Bardarbunga Volcanoa possible precursor to an eruption among several scenarios being considered, the Icelandic Meteorological Service said.
The aviation color code over the area has been changed from green to yellow as a precaution, the Met Office said, but the volcano's remote location in the heart of uninhabited southern Iceland means no infrastructure is at risk.
The series of seismic events continued for about three hours before subsiding a bit, according to the Met Office the statement said.
“Earthquakes continue to be felt in the area and it is too early to tell if the swarm will disappear,” the report said.
The largest earthquake was recorded at a magnitude of 5.1, while 17 other earthquakes of magnitude 3 or higher were recorded, including at least two of magnitude 4 or higher.
The Metabureau said the earthquakes were “consistent with rising inflation due to magma build-up” beneath Bardarbunga.
“The activity will be closely monitored, but at the moment it is difficult to say what the development will be,” the Met Service said.
The caldera or depression of the central Bardarbunga volcano covers about 25 square miles and is filled with ice.
It is one of six volcanic systems located under Europe's largest glacier, Vatnajökull.
In the event of a subglacial eruption, there is a risk of ash eruption and subglacial flooding from under Vatnajökull.
If the eruption had occurred outside the glacier, it would have been a lava eruption, the Met Office explained.
“Seismic activity in Bardarbunga has increased in recent months,” it said, and Tuesday's quake was the largest since Bardarbunga's last eruption in 2014-2015, which lasted six months.
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“Bardarbunga is unique in that it is an unusually large volcanic system partially covered by a glacier, and several scenarios are possible,” the agency notes. “During the 2014-2015 eruption, there was extensive research, hazard assessment and contingency planning that will prove valuable in the event of further volcanic activity.”
This eruption produced the largest basaltic lava flow in Iceland in over 230 years, but caused no damage or injury.
Iceland saw seven volcanic eruptions in the year near the southwestern fishing village of Grindavik, which led to the evacuation of the town. After the seventh eruption, people were evacuated from approximately 50 houses in Grindavik, reports the National Civil Defense Agency.
Iceland is home to 33 active volcanic systems, more than any other European country.
It sits atop a fault between two tectonic plates, making the island nation vulnerable to earthquakes and volcanic eruptionswhich have rocked parts of the country and displaced residents in recent years.