Why did this happen?

Please make sure your browser supports JavaScript and cookies and that you are not blocking them from loading. For more information you can review our Terms of Service and Cookie Policy.</s>Iceland's Met Office has warned that the Katla volcano could be on the verge of erupting, following the country's first major tremors since 1977.

Two earthquakes exceeding four in magnitude rocked the volcano's crater on Monday, according to a statement from Iceland 's Met Office.

Katla, which is one of the country's largest volcanoes , is located on the island's southern coast and stands 1,450 metres (4,757 feet) tall.

The volcano last erupted in 2011, and before that in both 1999 and 1955, but none of these eruptions were strong enough to break the ice covering its 10km-wide crater.

The massive volcano's last major eruption took place in 1918 and saw ash spewed into the air for nearly five weeks.

The volcano's ice cap is thought to be able to contain hot lava for around 90 minutes in the event of an eruption.

This would enable Icelandic authorities to evacuate anybody nearby and to alert international air traffic control.

In 2010, the eruption of Eyjafjallajokull resulted in a massive ash cloud that caused the cancellation of 100,000 flights across Europe and left many people stranded.

It was feared that tiny glass-like particles formed from the volcano's lava could melt in aircraft engines and cause turbines to become clogged.</s>A volcanic eruption in Iceland could be imminent after two earthquakes struck in rapid succession.

The Katla volcano, one of the largest in Iceland, was rocked by two earthquakes of magnitude 4.2 and 4.5 this weekend.

It typically erupts every 80 years but was last active in 1918, almost a century ago.

The remote North Atlantic country hit headlines in April 2010 when ash from the erupting Eyjafjallajokul volcano grounded flights across Europe for days.

Travel chaos ensued and left millions stranded at airports unable to travel home, including families and teachers on holiday during the school Easter break.

The Icelandic Meteorological Office has not yet changed the alert status for Katla from “normal” as no tremors have been recorded.

Katla has experienced various earthquake swarms over the last 10 years, but none as large as this weekend’s since 1977.

Gunnar Gudmundsson, a geophysicist, said that authorities are monitoring the situation and described it as "a little bit unusual", but said there's "no sign" of an eruption.</s>The Katla volcano has not erupted properly since 1918 and scientists say it is overdue to do so, although an eruption could still be decades away.

"It is quite a dynamic situation now, in the next hours and days following this, but as we speak at the moment we do not see any signs that there is an imminent hazardous unrest about to happen," Matthew Roberts, a natural hazards scientist at the Icelandic Met Office, said.

Ash from an eruption of the nearby Eyjafjallajokull volcano in 2010 shut down much of Europe's airspace for six days.

Katla, in southern Iceland, was rocked by quakes of magnitude 4.5 and 4.6 overnight. The volcano sustained similar movements in 2011.

The volcano is covered by an ice cap, which should, in the event of an eruption, typically contain the lava for around 60 to 90 minutes, giving time to alert the population and international air traffic, Roberts said.</s>LONDON (AP) — Iceland's Meteorological Office says two earthquakes early Monday rocked the caldera of Katla, one of the country's largest volcanos.

Gunnar Gudmundsson, a geophysicist, said authorities are monitoring the situation at the volcano in southern Iceland and described it as "a little bit unusual." The quakes measured magnitude 4.2 and magnitude 4.5 and were followed by some 20 aftershocks.

"People have been waiting for an eruption for 50 years," Gudmundsson said of Katla. "But there is no sign of an eruption."

Katla, named after an evil troll, is in southern Iceland about 140 kilometers (87 miles) from the capital, Reykjavik.

Iceland, an island nation in the remote North Atlantic, is a volcanic hotspot often hit by seismic activity. Its volcanos attracted international attention in April 2010, when ash from an eruption of its Eyjafjallajokull volcano grounded flights across Europe for days, disrupting travel for millions.

In the past, Katla has erupted in tandem with Eyjafjallajokull. Katla's last major eruption took place in 1918, and another has been expected since the 1960s.</s>Iceland's Meteorological Office says two earthquakes have rocked the caldera of Katla, one of the country's largest volcanos.

Gunnar Gudmundsson, a geophysicist, said Monday that authorities are monitoring the situation and described it as 'a little bit unusual,' but said there's 'no sign' of an eruption.

Gudmundsson says 'people have been waiting for an eruption for 50 years.'

Named after an evil troll, Katla typically awakens every 80 years or so and last erupted in 1918.

Iceland, in the remote North Atlantic, is a volcanic hotspot often hit by seismic activity.

Its volcanos attracted international attention in April 2010, when ash from an eruption of its Eyjafjallajokul volcano grounded flights across Europe for days, disrupting travel for millions.

In 2014, a record-breaking volcanic eruption spewed lava and ash over Iceland’s Highlands for nearly six months, leaving behind the largest caldera formation ever observed.

Katla is among the most frequently erupting volcanoes in Iceland, averaging about two eruptions each century. The volcanic massive is partly covered by the glacier Mýrdalsjökull which fills a caldera depression and covers the eruptive vents. The eruptions are accompanied by enormous laharic floods which have formed a vast sandur plain. The last eruption in Katla occurred in 1918. The Southern coast was extended by 5 km by the laharic flood deposits. The last eruption in Katla (pictured) occurred in 1918.

The Bardarbunga eruption was the strongest of its kind in Europe in more than 240 years, and released two cubic kilometers of volcanic material.

Researchers from the GFZ German Research Centre for Geosciences have studied the event in new detail, using satellite images, seismological and geochemical data, GPS data, and modelling to document the eruption.</s>The volcano, which stands at 1,500 meters (nearly 5,000 feet) tall, hasn't had a major eruption since 1918. Scientists say Katla usually erupts once every 50 years.

The meteorological office confirmed an increase in seismic activity in recent weeks and said it was monitoring the situation. An eruption is not imminent, scientists said, but they can't rule it out.

"Such summertime increases in seismicity are common at Katla and the ongoing activity within the caldera is similar to summertime unrest observed in 2012 and 2014," the office said.

"Measurements around Katla are not detecting signs of increased ground deformation or seismic tremor, both of which could be indicators of magma movement." Ash billows from the Eyjafjallajokull volcano on May 8, 2010 in Hvolsvoellur, Iceland. In 2010, Katla's neighboring volcano, Eyjafjallajokull, caused chaos across Europe and shut down most of the continent's airspace. Thousands of flights were grounded because of the volcanic ash following its eruption.
Numerous tremors rock the Katla volcano in Iceland prompting the government to raise the alarm level.