Mount Helka (Flickr/The Seclunatic)

Scientists in Iceland warn that the country's most feared volcano could erupt at any time.

One of the Iceland's most active stratovolcanoes, Mount Helka has erupted four times since 1970 at a rate of about once every ten years.  The 4892 feet (1491m) volcano's last eruption was on February 26, 2000 and scientists fear that it may be due for its next.

University of Iceland geophysicist Pall Einarsson told the Iceland Review on Wednesday that measurement instruments have shown unusual magma movements around the Hekla volcano in recent days. He added, however, that it could not be stated with any certainty that the activity picked up by sensors at the volcano in south Iceland is a signal of an imminent eruption.

Nevertheless, civil disaster authorities and local emergency authorities in the country were notified on Wednesday of the possibility of an eruption.  Helka continue to be monitored closely as its eruptions usually start without much advanced warning.

Known as the Gateway to Hell in the Middle Ages, Helka is Iceland's most famous and historically active volcano.  It is located west of Iceland's southeast volcanic rift-zone, close to the Eyjafjallajokull volcano, which erupted last year and emitted a massive ash cloud that spread across Europe and forced the cancellation of thousands of airline flights a day.

This past May, another Icelandic volcano, Grimsvotn, erupted putting more ash into the air in 36 hours than Eyjafjallajokull did in a month.  However, flight delays were far fewer because prevailing winds pushed the ash away from populated areas.

Are we in for more trouble in the skies with Helka?

Here's the good news:  Geophysicist Ari Trausit Gudmundsson told Agence-France Presse that Hekla usually erupts with both lava and ash and if the next eruption is of the same character (as the previous ones), it is unlikely that it will have any effects on flights in Europe.

However, geologists have warned that Iceland's volcanoes appear to have entered a more active phase.  More eruptions than usual are to be expected, with Helka believed to be at the front of the line.