is an Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...
A stratovolcano, also known as a composite volcano, is a tall, conical volcano built up by many layers of hardened lava, tephra, pumice, and volcanic ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile and periodic, explosive eruptions...
located under the ice cap of Vatnajökull
Vatnajökull is the largest glacier in Iceland. It is located in the south-east of the island, covering more than 8% of the country.-Size:With an area of 8,100 km², Vatnajökull is the largest ice cap in Europe by volume and the second largest in area Vatnajökull is the largest glacier in...
glacier, rising to 2,009 m (6,591 feet) above sea level, making it the second highest mountain in Iceland, just about 101 m lower than Hvannadalshnjúkur.
Bárðarbunga the glacier is a large and powerful Stratovolcano. It is also Iceland's largest volcanic system, considered to be close to 200 km long and up to 25 km wide. The volcano is covered in ice hiding her massive glacier-filled crater.
Bárðarbunga was a little known volcano in Iceland because of its location far away from settlement and infrequent eruptions. However Icelanders have learned to respect this large and powerful volcano. Bárðarbunga's highest spot is 2009 meters high and is the second highest mountain in the country.
The main crater in Bárðarbunga is about 70 square kilometers, up to 10 km wide and about 700 meters deep. The surrounding edges rise up to 1850 meters but the base is on average close to 1100 meters. The crater is completely filled with ice.
Many tephra layers originally thought to belong to other volcanoes have in the recent studies proved to be from Bárðarbunga. The Gjálp eruption in 1996 revealed that an interaction may be between Bárðarbunga and Grímsvötn
The Grímsvötn sub-glacial lakes and the volcano of the same name are in South-East Iceland. They are in the highlands of Iceland at the northwestern side of the Vatnajökull ice-cap. The lakes are at , at an elevation of...
. A strong earthquake in Bárðarbunga, about 5 on the Richter, is believed to have started the eruption in Gjálp.
Sustained seismic activity has been in Bárðarbunga for some years without an eruption, which indicates the volcano is still active.
Bárðarbunga volcano is specific to the extent that there is frequent volcanic activity outside the glacier to the southwest in the highlands between Vatnajökull and Mýrdalsjökull
Mýrdalsjökull mire dale glacier" or " mire valley glacier") is a glacier in the south of Iceland. It is situated to the north of Vík í Mýrdal and to the east of the smaller glacier Eyjafjallajökull. Between these two glaciers is Fimmvörðuháls pass. Its peak reaches in height and in 1980 it covered...
, also to the northeast toward Dyngjufjöll. The largest eruptions appear to be when magma rushes southwest.
In historic times there have been large eruptions every 250–600 years. The largest lava flow in Iceland and the entire earth from a single eruption is originated from Bárðarbunga about 8500 years ago. The lava is believed to be 21–30 cubic kilometers and covers approximately 950 square kilometers (VEI 6). Several similar-sized eruptions have been recorded in the past 10000 years.
Many large prehistoric eruptions have occurred southwest of the glacier and two after settlement in Iceland, Vatnaöldur eruption about 870 and Veiðivötn eruption 1480. Both were very large eruptions that would have major effects on life in Iceland and neighboring countries were they to repeat in modern times.
Smaller eruptions are frequent northeast of Bárðarbunga in an ice-free area called Dyngjuháls. Such an eruption last occurred in 1862-4.
Studies of tephra layers have shown that a number of eruptions have occurred beneath the glacier itself, probably in the northeast of the crater or in Bárðarbunga. These eruptions appear to follow a cycle, several eruptions were in the glacier between 1701–40 and since 1780. There has been an eruption in the glacier or the system since 1864. Frequent earthquakes in Bárðarbunga indicate that the volcano will erupt sooner or later.
In September 2010, an earthquake swarm occurred near Bárðarbunga, with over 30 earthquakes recorded on 26 September, the largest quakes measuring 3.5 and 3.7 on the Richter scale.
Dangers from eruptions
Large volcanic fissure
A fissure vent, also known as a volcanic fissure or simply fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is usually a few meters wide and may be many kilometers long. Fissure vents can cause large flood basalts and lava channels...
eruptions occur every 5-800 years in Iceland. They often occure in the Veiðivötn area, south-west of the Bárðarbunga central volcano. Such an eruption would endanger many of Iceland's hydroelectric power plants as each eruption changes the landscape dramatically. Tephra from a large eruption from the Bárðarbunga volcanic system could affect flight traffic and temperature in northern parts of the world.