|Map of Iceland showing locations of these volcanoesHekla|
Pall Einarsson, a geophysicist at the University of Iceland said that Katla, Hekla, Bardarbunga and Grimsvotn are restless.
Katla is the least recently-active volcano of the four, last erupting in 1918 but is now shaking with over magnitude three tremors. It averages about two eruptions each century. It's especially dangerous since it is partly covered by the glacier Myrdalsjokull which fills a caldera depression and covers the eruptive vents so when it does go off it releases hot molten mud flows called Lahars. These are uber Lahars, the last eruption in 1918 extended the southern coast by 5km just with laharic deposits.
Hekla, otherwise know as the "Gateway to Hell" has been quiet for 16 years but data collected in June last year revealed it is building up magma, and it's internal pressure is currently higher than before its last two previous eruptions. It's ready to go, erupting once every 10 years, from 1970 to 2000, it's been dormant until now. Professor Einarsson said that tourists should stay away but what do you do with the 20-30 planes full of passengers flying right over the top of Hekla every day.
Bardarbunga volcano had a red alert issued at the end of August 2014 to February 2015 when it experienced a small eruption but only because it lies underneath the Vatnajokull glacier. The volcano sits in a 700metre caldera beneath ice but the majority eruptions come out of the fissures in the side. Not small fissures either, the Veidivotn fissure extends for over 62 miles to the south west almost reaching Torfajokull volcano while the Trollagigar fissure extends 31 miles to the north east towards the Askja volcano.
The last eruption was the strongest of its kind in Europe in more than 240 years and with earthquakes starting up, it suggests that magma could be building below the surface.
Grimsvotn is a near neighbour to Bardarbunga and likely to be fuelled by the same source of magma. It erupted in 2011, sent a huge plume of ash skywards leading to flights being grounded. Seismic activity is steadily rising.
These are only four of the volcanoes that dot the island of Iceland. Between the lot of them you have just about every kind of volcanic activity documented. All we need now is for the other side of the world to start rumbling, Yellowstone is already doing that but I mean rumbling in a really vicious Presidential kind of rumbling and then I might worry.