Why volcanic activity occurs in iceland

Due to the high level of fragmentation of material in hydromagmatic eruptions, the ash clouds they produce may contain a significant proportion of fine ash, increasing the likelihood of long-distance transportation in the atmosphere. The interval between individual volcanic eruptive episodes is far from predictable, but with a volcano erupting in Iceland on average every 5 years, and with around three-quarters of eruptions producing ash, we need to remain alert to the threat.

Stevenson of the University of Edinburgh for their assistance with resources and reviews. Thanks also to the Icelandic Met Office for supplying the map of volcanoes. Swindles, G. Plunkett , A yr perspective on volcanic ash clouds affecting northern Europe, Geology, v. Thordarson, T. Larsen , Volcanism in Iceland in historical time: Volcano types, eruption styles and eruptive history, Journal of Geodynamics, 43, Volcanic activity in Iceland.

It may involve a similar amount of magma as the current eruption, or it could release significantly more. Historical accounts and layers of ancient volcanic rock suggest that each time this area experiences a significant increase in earthquakes, it culminates in several decades of eruptions, jumping from fissure to fissure all over the peninsula. The small and relatively safe eruption occurring now therefore provides a stellar opportunity for scientists and emergency managers to prepare for possible bursts of lava to come.

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Environment As the EU targets emissions cuts, this country has a coal problem. Paid Content How Hong Kong protects its sea sanctuaries. In Iceland it can be just a few kilometres thick as opposed to km thick in much of Europe. Tectonic movements and mounting pressure cause the thin crust to crack, forming swarms of fissures below and at the surface.

Magma enters the fissures and when it reaches the surface, it causes a volcanic eruption. Strato volcanoes, e. These are volcanic systems which erupt repeatedly over thousands, even millions of years and build up substantial mountains, topped by a crater. Hekla is a strato volcano, but differs from the others in that it is formed along a ridge.

Central volcanoes, with an underlying magma chamber, which feeds surrounding fissure swarms, e. Calderas are often present, forming when subsidence follows sudden emptying of the magma chamber, whose roof collapses.

Fissure swarms and crater rows, e. Each volcanic system can be as many as tens of kilometres in length and several kilometres wide. On average there is one eruption in Iceland every 5 years but during the last years, eruptions have been more frequent. Most eruptions in Iceland are rather short-lived, lasting only a matter of days or at most a few weeks, but occasionally like that of Surtsey , they can last several years. One hundred years of eruptions in Iceland.

Almost all types of volcanic activity found on earth occur in Iceland and the range of volcanic features is extensive and of great interest to study groups as well as general enthusiasts. Rows of cinder or scoria craters form when lava fountains concentrate activity at several vents along a fissure and the material builds up around the vent.

Such craters are not usually very high. The longest crater row in Iceland is the Laki crater row where craters are strung out along a 25 km long fissure. Volcanoes produce acidic rhyolite or basic basalt rocks and sometimes both types. The best known rhyolite mountains in Iceland are those around Landmannalaugar. The center of the field resembled carbonized oatmeal.

The lava near the path reached out with giant panther paws that seemed to demand petting. I encountered a few people here, crouching and cautiously touching the lava.

Even so, this had to be the spot that a friend of mine was so concerned about. I touched the hardened lava. There are guidelines, in Iceland, for naming lava.

Naming it for a living person is discouraged. Proposals must be approved by the Ministry of Education, Science, and Culture. They decided on a poetic mouthful of a name, Fagradalshraun —the Lava of the Beautiful Valley. The path curved up and around another hill before descending to a land bridge that, after sixty feet or so, connected to a final rise: Goggle Hill. I passed two women, their faces blearily serene as they stutter-stepped over loose rocks.

The lava field that people had been touching was to the right of the land bridge. To its left was an equally large lava field. I might have paused to marvel at being surrounded by lava were I not so preoccupied with the evident difficulty of traversing the narrow, exposed ridge leading up Goggle Hill. The steep slopes on each side of the ridge led directly to the edge of the lava fields. If I lost my balance, I could tumble sixty or seventy feet and roll to a painful, and possibly fatal, stop against a knife-sharp, smoking barrier.

As I began to climb, the wind gusts sounded like a revving jet engine. A man with a big camera took refuge behind a boulder, as if he were a war photographer.

A woman coming toward me inched down the incline on her bottom. Whenever I heard the revving noise, I dropped to one knee and grabbed the nearest large rock, waited until the wind decreased slightly, and then hurry-crawled toward the summit of Goggle Hill. Finally, I was at the top, and there it was: the eruption, maybe six hundred feet away, the crater at eye level. About twenty people sat with their boots dug into the dirt, to keep them from sliding over the edge.

As I secured my pack behind a rock, the crater was just finishing a spasm. It made thick sloshing noises, like a loudly digesting stomach.

Then it fell quiet. To the left of the bow was a valley shaped like a gigantic bowl. This was Geldingadalur Valley—Castration Valley. The lava there had a smooth black crust, swirled in some places and buckled in others. The lava gushed over the notch and fed the molten river. Bits of hardened crust floated along the top, resembling shards of black ice.

A giant red-orange boulder flew about forty feet into the air, then landed and rolled halfway down the slope. Within seconds, it had seized in place, turning the color of ash. The crater released an oceanic roar that filled my whole body. Even at a distance, I could feel the intense heat of the fire geyser on my face. If I closed my eyes, I was at the beach on a hot day, and had just emerged from the freezing water and was about to take a nap in the sun. People chatted in groups.

A woman in black athleisure wear and puzzlingly pristine white sneakers greeted everyone, in American-accented English, as she made her way to the edge. Mostly, however, the scene was contemplative. There was none of the cathartic partying from the early days of the eruption, unless an Icelandic man and woman—he was drinking beer—counted as holdovers. She was named after the volcano.

The Black Sea, which had an average depth of about two hundred feet, had buried that moment in the past, in what seemed already to be a distant geological era. From my high perch on Goggle Hill, I could admire the different textures of the lava fields. In some places, the surface was shirred and shiny; in others, it was dull, rust-colored, and blocky.

This controls how fast the lava is moving and how easily it shears and how quickly bubbles are released, and also how quickly it forms a shiny crust and how quickly it oxidizes. Just beneath me, a bright-orange puddle, streaked with blue, bubbled up in the middle of what had seemed to be an inactive lava field. The puddle steadily grew as the surrounding surface melted away. Then a second puddle opened beside it, widening with the speed of film dissolving in a projector.

Gas emanating from the puddles made my lungs constrict, causing light-headedness. The crater erupted. It fell dormant. It erupted.