 |
| Thordarhyrna | |
|---|---|
  Thordarhyrna | |
| Highest point | |
| Listing | List of volcanoes in Iceland |
| Coordinates | 64°12′4″N17°0′17″W / 64.20111°N 17.00472°W |
| Geology | |
| Mountain type | Subglacial volcano |
| Last eruption | 1910 |
Thordarhyrna (Icelandic : Þórðarhyrna [ˈθourðarˌhɪ(r)tna] ) is one of seven [1] subglacial volcanoes beneath the Vatnajokull glacier in Iceland.
It last erupted in 1910 and prior to that in 1903. [2] [3]
An eruption in 3550 BC ± 500 years poured out 150,000,000 cubic meters of lava in the area of Bergvatnsárhraun, to the south of Thordarhyrna. [4]
There is a mechanical interaction between Thordarhyrna and Grimsvötn, despite these volcanoes being relatively far apart, [6] so the eruption in 1902 - 1904 was combined with an eruption from Grimsvötn and had a Volcanic Explosivity Index (VEI) of 4. [7]
A fault runs (N.35°W) from Thordarhyrna towards Hamarinn, and separates two different tectonic regions. [8]
Vatnajökull is the largest and most voluminous ice cap in Iceland, and the second largest in area in Europe after the Severny Island ice cap of Novaya Zemlya. It is in the south-east of the island, covering approximately 10% of the country.
Iceland experiences frequent volcanic activity, due to its location both on the Mid-Atlantic Ridge, a divergent tectonic plate boundary, and over a hot spot. Nearly thirty volcanoes are known to have erupted in the Holocene epoch; these include Eldgjá, source of the largest lava eruption in human history.
The Highland of Iceland is an area that comprises much of the interior land of Iceland. Iceland is known for its volcanic landscapes, numerous glaciers and the astonishing colors of its Highlands. It is often mistakenly called Highlands, as in the Scottish Highlands. The Highland is situated above 300–400 meters and is mostly uninhabitable. The soil is primarily volcanic ash, and the terrain consists of basalt mountains and lava fields. Snow covers the Highland from October until the beginning of June. A few oasis-like areas such as Herðubreiðarlindir and Þórsmörk are also found in the Highland. The Highland has many natural wonders and hiking trails.
Katla is an active volcano in southern Iceland. This particular volcano has been very active historically with at least twenty documented major eruptions since 2920 BCE. In its recent history though, Katla has been less active as the last major eruption occurred in 1918. These eruptions have had a Volcanic Explosivity Index (VEI) of between 4 and 5 on a scale of 0 to 8. In comparison, the Eyjafjallajökull 2010 eruption had a VEI of 4. Larger VEI-5 eruptions are comparable to Mount St. Helens 1980 eruption. Several smaller (minor) eruptions measuring VEI-1 and below have occurred since, with the most recent being in 1999.
Öræfajökull is an ice-covered volcano in south-east Iceland. The largest active volcano and the highest peak in Iceland at 2,110 metres (6,920 ft), it lies within the Vatnajökull National Park and is covered by part of the glacier.
Laki or Lakagígar is a volcanic fissure in the western part of Vatnajökull National Park, Iceland, not far from the volcanic fissure of Eldgjá and the small village of Kirkjubæjarklaustur. The fissure is properly referred to as Lakagígar, while Laki is a mountain that the fissure bisects. Lakagígar is part of a volcanic system centered on the volcano Grímsvötn and including the volcano Þórðarhyrna. It lies between the glaciers of Mýrdalsjökull and Vatnajökull, in an area of fissures that run in a southwest to northeast direction.
Grímsvötn is an active volcano with a fissure system located in Vatnajökull National Park, Iceland. The volcano itself is completely subglacial and located under the northwestern side of the Vatnajökull ice cap. The subglacial caldera is at 64°25′N17°20′W, at an elevation of 1,725 m (5,659 ft). Beneath the caldera is the magma chamber of the Grímsvötn volcano.
Pisgah Crater, or Pisgah Volcano, is a young volcanic cinder cone rising above a lava plain in the Mojave Desert, between Barstow and Needles, California in San Bernardino County, California. The volcanic peak is around 2.5 miles (4.0 km) south of historic U.S. Route 66-National Old Trails Highway and of Interstate 40, and west of the town of Ludlow. The volcano had a historic elevation of 2,638 feet (804 m), but has been reduced to 2,545 feet (776 m) due to mining.
A subglacial volcano, also known as a glaciovolcano, is a volcanic form produced by subglacial eruptions or eruptions beneath the surface of a glacier or ice sheet which is then melted into a lake by the rising lava. Today they are most common in Iceland and Antarctica; older formations of this type are found also in British Columbia and Yukon Territory, Canada.
The geology of Iceland is unique and of particular interest to geologists. Iceland lies on the divergent boundary between the Eurasian plate and the North American plate. It also lies above a hotspot, the Iceland plume. The plume is believed to have caused the formation of Iceland itself, the island first appearing over the ocean surface about 16 to 18 million years ago. The result is an island characterized by repeated volcanism and geothermal phenomena such as geysers.
Bárðarbunga, is an active stratovolcano located under Vatnajökull in Vatnajökull National Park which is Iceland's most extensive glacier. The second highest mountain in Iceland, 2,009 metres (6,591 ft) above sea level, Bárðarbunga is also part of a volcanic system that is approximately 200 kilometres (120 mi) long and 25 kilometres (16 mi) wide.
Vatnajökull National Park is one of three national parks in Iceland. It encompasses all of Vatnajökull glacier and extensive surrounding areas. These include the national parks previously existing at Skaftafell in the southwest and Jökulsárgljúfur in the north.
The 2011 eruption of Grímsvötn was a Plinian eruption of Grímsvötn, Iceland's most active volcano, which caused disruption to air travel in Northwestern Europe from 22–25 May 2011. The last eruption of Grímsvötn was in 2004, with the previous most powerful eruptions in 1783, 1873 and 1902. The Grímsvötn eruption was the largest eruption in Iceland for 50 years.
Skeiðarársandur is an Icelandic glacial outwash plain, a vast expanse of sand generated by the transport of debris by the Skeiðará and other rivers, whose flow is generated by the Skeiðarárjökull glacier and fed by the volcanic systems of Grímsvötn and Öræfajökull.
Holuhraun is a lava field just north of the Vatnajökull ice cap, in the Icelandic Highlands, in Suður-Þingeyjarsýsla, Northeastern Region, Iceland. The lava field was created by fissure eruptions. After a research expedition in 1880, the lava field was initially called Kvislarhraun[ˈkʰvɪstlar̥ˌr̥œiːn]. Four years later, it received its current name from geologist and geographer Þorvaldur Thoroddsen. Holuhraun was the site of a volcanic eruption which began on 29 August 2014 and produced a lava field of more than 85 km2 (33 sq mi) and 1.4 km3 (0.34 cu mi) – the largest in Iceland since 1783.
The Skaftá is a river in South Iceland. It is primarily glacial in origin and has had its course modified by volcanic activity; as a result of both, it often floods because of glacial melting.
Gjálp is a hyaloclastite ridge (tindar) in Iceland under the Vatnajökull glacier shield. It originated in an eruption series in 1996 and is probably part of the Grímsvötn volcanic system, though not all the scientists involved are of this opinion.
{{cite web}}: CS1 maint: archived copy as title (link) Figure 2.8 shows 7 volcanoes beneath the glacier  | This volcanology article is a stub. You can help Wikipedia by expanding it. |