Nature

Growing likelihood of eruption in South Iceland's Mount Hekla

By Staff

Hekla erupting in 2000 The pressure in the volcano's magma chambers today exceeds that which was reached prior to the last eruption in 2000. Photo/Vilhelm Gunnarsson.

Yesterday marked the 70 year anniversary of one of the largest volcanic eruptions in Iceland in the 20th century, the 1947-8 Hekla eruption. Today scientists say the mountain is clearly gearing up for another eruption, as the pressure in the volcano's magma chambers keeps increasing.

Only an hour's warning

While geologists can identify growing volcanic pressure and thus say that an eruption is more or less likely, it is impossible to predict the start of an eruption more than one hour in advance.

Read more: All of Iceland‘s major volcanoes showing unusually high levels of activity

"Most available measurements indicate Hekla is ready to burst anytime soon, but it is difficult to say when exactly," volcanologist Páll Einarsson told the local newspaper Morgunblaðið. The pressure in Hekla's magma chambers already exceeds the levels reached prior to the last two eruptions, in 1991 and 2000.

Regular eruptions since 1970

Hekla has erupted quite regularity since 1970, with one eruption every ten years. However, the last eruption took place in 2000. These eruptions were all relatively small, compared to the 1947 eruption which lasted 13 months and produced a 40 square kilometer lava field, while also adding 44 meters to the height of the mountain.

Hekla erupts in smaller fissures which open up in the sides of the mountain. Smaller eruptions have involved only a handful of smaller localized fissures, but in the 1947 eruption the entire mountain was described as having come on fire. Craters spewing lava pillars 800 meters up into the air opened up all along the top of the mountain.The thunderous noise from the eruption could be heard all over Iceland, from Reykjavík to the Westfjords and as far as Grímsey island off the North Coast of Iceland.

At the time Hekla had been lying dormant for 102 years leading many to proclaim the mountain had become extinct. The eruption proved that such judgments were very much premature, and that Hekla is still very much active!