|Mid-Atlantic Ridge above sea level at Iceland|
Iceland has many geysers, including Geysir, from which the English word is derived, and the famous Strokkur, which erupts every 5–10 minutes. After a phase of inactivity, Geysir started erupting again after a series of earthquakes in 2000. Geysir has since then grown quieter and does not erupt often.
With the widespread availability of geothermal power, and the harnessing of many rivers and waterfalls for hydroelectricity, most residents have access to inexpensive hot water, heating and electricity. The island itself is composed primarily of basalt, a low-silica lava associated with effusive volcanism as has occurred also in Hawaii. Iceland, however, has a variety of volcanic types (composite and fissure), many producing more evolved lavas such as rhyolite and andesite. Iceland has hundreds of volcanoes within approx. 30 volcanic systems active
Surtsey, one of the youngest islands in the world, is part of Iceland. Named after Surtr, it rose above the ocean in a series of volcanic eruptions between 8 November 1963 and 5 June 1968. Only scientists researching the growth of new life are allowed to visit the island.
On 21 March 2010, a volcano in Eyjafjallajökull in the south of Iceland erupted for the first time since 1821, forcing 600 people to flee their homes. Further eruptions on 14 April forced hundreds of people to abandon their homes. The resultant cloud of volcanic ash brought major disruption to air travel across Europe.
Another large eruption occurred on 21 May 2011. This time it was the Grímsvötn volcano, located under the thick ice of Europe's largest glacier, Vatnajökull. Grímsvötn is one of Iceland's most active volcanoes and this eruption was much more powerful than the 2010 Eyjafjallajökull activity. The eruption hurled ash and lava 20 km (12.43 mi) up into the atmosphere, creating a large cloud that for a while was thought to pose a danger to jet aircraft over a wide area of northern Europe.
Volcanology of Iceland
|Active volcanic areas and systems in Iceland|
Iceland has a high concentration of active volcanoes due to its location on the mid-Atlantic Ridge, a divergent tectonic plate boundary. The island has 30 active volcanic systems, of which 13 have erupted since the settlement of Iceland in AD 874.
Of these 30 volcanic systems, the most active/volatile is Grímsvötn. Over the past 500 years, Iceland's volcanoes have erupted a third of the total global lava output.
The most fatal volcanic eruption of Iceland's history was the so-called Skaftáreldar (fires of Skaftá) in 1783-84. The eruption was in the crater row Lakagígar (craters of Laki) southeast of Vatnajökull glacier. The craters are a part of a larger volcanic system with the subglacial Grímsvötn as a central volcano. Roughly a quarter of the Icelandic nation died because of the eruption. Most died not because of the lava flow or other direct effects of the eruption, but from indirect effects, including changes in climate and illnesses in livestock in the following years caused by the ash and poisonous gases from the eruption. The 1783 eruption in Lakagígar is thought to have erupted the largest quantity of lava from a single eruption in historic times.
The eruption under Eyjafjallajökull ("glacier of Eyjafjöll") in 2010 was notable because the volcanic ash plume disrupted air travel in northern Europe for several weeks; however this volcano is minor in Icelandic terms. In the past, eruptions of Eyjafjallajökull have been followed by eruption of the larger volcano Katla, but after the 2010 eruption no signs of an imminent eruption of Katla were seen.
The eruption in May 2011 at Grímsvötn under the Vatnajökull glacier sent thousands of tonnes of ash into the sky in a few days, raising concerns of a repeat of the travel chaos seen across northern Europe.