16,000,000 years ago - the oldest known rock in Iceland was formed in a lava eruption. The age of the basaltic strata from west to east is 16–10 million years. (See Geology of Iceland - Origins)
Circa 3,200,000-1,800,000 years ago (Plio-Pleistocene) - Esjan (Esja) - The western part is about 3.2million years and the eastern part is about 1.8million years. The movements of the plate boundaries are continually moving the strata to the west and away from the active volcanic zone. Two volcanoes were active in the Reykjavík region, Viðey volcano and Stardals volcano. They partially formed Esja (Esjan); the smaller mountains near Reykjavík; plus the islands and small peninsulas like Viðey and Kjalarnes.(Part of the Reykjanes volcanic zone (RVZ))
2,600,000-9,000 years ago - Viðey (caldera), at Reykjavík. The underwater eruption that formed Viðey island stopped circa 9,000 years ago. (Part of the Reykjanes volcanic zone (RVZ))
2,500,000-11,000 years ago. Keilir was formed during a subglacial fissure eruption which thawed the ice and formed a subglacial lake, and caused explosive activity. Ice thickness and more exact time of eruption are not known, just that it took place during the Pleistocene (Weichselian).(Part of the Reykjanes volcanic zone (RVZ))
42,000-12,400 years ago - Sveifluháls, volcanic melting of glacier ice induced the formation of one or more subglacial meltwater lakes. Dropping overburden pressures lead to the eruption of vitric phreatomagmatic tuff.
Circa 10,600 years ago - Katla. It is thought that Katla is the source of more than 6 to 7 cubic kilometers (1.4 to 1.7cumi) of tephra 'Vedde Ash' found at a number of sites including Vedde in Norway, Denmark, Scotland and North Atlantic cores.
6700 BC. - the "Great Þjórsá Lava flow", the largest known effusive eruption in Iceland in the last 10,000 years, originated from the Veiðivötn (is:Veiðivötn) area. The Þjórsá lava field is up to 1,000km2 (390sqmi) in area and flowed over 100km (62mi) to the sea and forms the coast between Þjórsá and Ölfusá.(Part of the East volcanic zone (EVZ))
Circa 5,800 BC - Hveravellir? The Kjalhraun (hraun means "lava field") lava field is about 7,800 years old.
5000 BC - Hekla (H5). The first acidic eruption in Hekla. The ash layer H5 is found in soil in the central highlands and in many parts of the North. (Part of the East volcanic zone (EVZ))
3500 BC - Grímsnes, VEI 3. The Grímsneshraun lava-fields in the area cover a total of 54km2 (21sqmi). The total volume of lava produced in the lava flows of Grímsnes has been estimated at 1.2 cubic kilometres (0.29cumi). (Part of the South Iceland Seismic Zone (SISZ))
1200 BC - Veiðivatnasvæði, Búrfellshraun flowed from a series of craters near Veiðivötn (is:Veiðivötn), on the one hand to Þórisós and on the other hand down with Tungná and Þjórsá all the way down to Landsveit
Circa 1,000-900 BC - Hekla (H3) is considered the most severe eruption of Hekla during the Holocene. which threw about 7.3 cubic kilometres (1.8cumi) of volcanic rock into the atmosphere, placing its Volcanic Explosivity Index (VEI) at 5. This would have cooled temperatures in the Northern Hemisphere for several years afterwards. Traces have been identified in Scottish peat bogs, and dendrochronology shows a decade of negligible tree ring growth in Ireland.(Part of the East volcanic zone (EVZ))
800 BC (± 300 years) - Fremrinámur. It is at the junction of the Mid-Atlantic Ridge and the Greenland–Iceland–Faeroe Ridge. It is one of five volcanic systems found in the axial rift zone in north east Iceland.(Part of the North volcanic zone (NVZ))
300 BC Mývatn, large fissure eruption pouring out basaltic lava. The lava flowed down the valley Laxárdalur to the lowland plain of Aðaldalur where it entered the Arctic Ocean about 50km (31mi) away from Mývatn. The crater row that was formed on top of the eruptive fissure is called Þrengslaborgir (or Lúdentarborgir). (Part of the North volcanic zone (NVZ))
Dates are approximate.(Note: First Norse settlers arrived in 870/874.)
circa 800 - Vatnafjöll. a 40km (25mi) long, 9km (6mi) wide basaltic fissure vent system. It is part of the same system as Hekla. More than two dozen eruptions have occurred at Vatnafjöll during the Holocene Epoch.(Part of the East volcanic zone (EVZ))
870 - Ash and lava eruptions in Vatnaöldur. The craters resulted from 65 kilometres (40mi) (or 42 kilometres (26mi)) long volcanic fissures within the area of a lake. The mainly explosive eruptions emitted 5–10km3 (1.2–2.4cumi) of tholeiite basalt.(It is part of the East volcanic zone (EVZ))
934 (or 939) - Katla and Eldgjá: VEI 6. A large lava flow from Eldgjá flowed over Álftaver (is: Álftaver), Meðalland and Landbrot (is: Landbrot). The eruption was the largest flood basalt in historic time (800 square kilometres (310sqmi),18 cubic kilometres (4.3cumi) of magma.) Evidence from tree rings in the Northern Hemisphere indicates that 940 was one of the coolest summers in 1500 years. Summer average temperatures in Central Europe, Scandinavia, Canada, Alaska, and Central Asia were 2°C lower than normal. Probably the earthquake from which Molda-Gnúpur and his people fled according to "Settlement". Landnáma also tells about the formation of Sólheimasandur (:is: Sólheimasandur]]) in the great course of the Jökulsá river. (Part of the East volcanic zone (EVZ))
940 - Vatnajökull / Veiðivötn (is:Veiðivötn) (volcanic layer in NA-land[clarification needed]) (Part of the East volcanic zone (EVZ))
Circa 1,000 - Hveravellir. A volcanic system in the Arnarvatnsheiði. The craters of this system produced the lava field Hallmundarhraun which extends some 50 kilometres (31mi) westward into the valley of the Hvítá.
1104 - Hekla (H1). Its first and greatest eruption in historical time. Heavy ash fall to the north and northeast. Þjórsárdalur was destroyed, incl. the town of Stöng (Þjóðveldisbærinn Stöng) (is: Stöng (bær)). (Part of the East volcanic zone (EVZ))
1158 - Hekla, second eruption. A VEI 4 eruption began on 19 January 1158 producing over 0.15km3 of lava and 0.2km3 of tephra. It is likely to be the source of the Efrahvolshraun lava on Hekla's west.(Part of the East volcanic zone (EVZ))
1226-1227 - some eruptions in Reykjanes. They are owned[clarification needed] by Yngra Stampahraun, (Klofningahraun), Eldvarpahraun, Illahraun and Arnarseturshraun. Sandy winter due to a large ash eruption at Reykjanestá and the so-called Medieval Valley fell. Hardness as a result. (Part of the Reykjanes volcanic zone (RVZ))
1311 - Katla. Darkness in the Eastfjords and ash fall in many parts of the country. Major lava flow, probably on Mýrdalssandur, but sources are unclear and contradictory. Crop and hay failure the following year with associated casualties. (Part of the East volcanic zone (EVZ))
1341 - Hekla, eruption number 6. The ash spread west through Borgarfjörður and Akranes. Great death, especially in Rangárvellir (is: Rangárvellir) and many settlements were destroyed. (Part of the East volcanic zone (EVZ))
1362 - Knappafellsjökull. The largest ash eruption in Icelandic history. Litla-Hérað (Öræfasveit) was completely destroyed and few seem to have escaped. The group was called Öræfi when it started to rebuild and the glacier Öræfajökull. Most of the ash was carried east to the sea, but destroyed much of Hornafjörður and Lónshverfi along the way. Jökulhlaup to Skeiðarársandur and out to sea. (Part of the Öræfajökull volcanic belt (OVB))
1372 - north-west of Grímseyjar
1389-1390 - in and around Hekla, eruption number 7. Norðurhraun lava flows, Skarð, Tjaldastaðir and maybe more towns are subsumed.(Part of the East volcanic zone (EVZ))
1510 - Hekla eruption number 8. A large eruption with heavy ash fall to the south. The largest Hekla lava field from historical times. Extensive land degradation in Rangárvallasýsla as a result. (Part of the East volcanic zone (EVZ))
1554 - Vondubjallar southwest of Hekla. The eruption lasted for 6 weeks in the spring. Red bells formed and from them flowed Pálssteinshraun. (Part of the East volcanic zone (EVZ))
1625 - Katla. September 2–14 . Large eruption with heavy ash fall to the east. 25 towns were deserted. Þorsteinn Magnússon, abbot of Þykkvabær, wrote a report on the eruption, the first of its kind in Iceland. (Part of the East volcanic zone (EVZ))
1660-61 - Katla. The eruption began on November 3 and lasted until the end of the year. A small ash fall but a large flow on Mýrdalssandur and cut Höfðabrekka off. (Part of the East volcanic zone (EVZ))
1693 - Hekla, eruption number 11 began on 13 February and lasted until the autumn. Heavy ash fall to the northwest at the beginning of the eruption which caused great and permanent damage in the surrounding areas. (Part of the East volcanic zone (EVZ))
1724-29 - Mývatnseldar (is:Mývatnseldar) (Myvatn Fires, Krafla Fires). Lava flowed into Lake Mývatn and the volcanic "Viti crater" (Hell crater) formed by Krafla volcano.(Part of the North volcanic zone (NVZ))
1755-56 - Katla. The eruption began on October 17 and lasted until mid-February. A large amount of ash, about 1.5km3 (0.36cumi), reached the northeast and caused great damage in Skaftártunga, Álftaveri and Síða. A big lava flow on Mýrdalssandur, mostly west of Hafursey. Lightning killed two people. About 50 towns were deserted, most of them only temporarily. (Part of the East volcanic zone (EVZ))
1766-68 - Hekla, eruption number 12. The largest lava eruption of Hekla in historical time. Ash fall in Húnavatns- and Skagafjarðarsýsla counties. 10 lands were deserted. (Part of the East volcanic zone (EVZ))
1783-84 Laki. ( Skaftáreldar, Grímsvötn, Þórðarhyrna, sometimes referred to in Icelandic as the Skaftáreldur, Skaftá Fires) Lava flowed along Skaftá river valley and Hverfisfljót, down into the lowlands and covered about 580km2 (220sqmi) (including a gorge thought to have been 200 metres (660ft) deep). The eruption has been estimated to have killed over six million people globally. Ash fall and poisoning caused hay failure leading to a famine that killed about 25% of the island's population and resulted in a drop in global temperatures, as sulfur dioxide was spewed into the Northern Hemisphere. This caused crop failures in Europe and may have caused droughts in India.(Part of the East volcanic zone (EVZ))
1845-46 - Hekla, eruption number 13 began on September 2 and lasted for about 7 months. Heavy ash fall to the southeast and a lava flow in Ytri-Rangá. Lava flowed west and northwest, about 25km2 (9.7sqmi), so the town of Næfurholt had to be relocated. (Part of the East volcanic zone (EVZ))
1875 - Askja. A lava eruption began in Sveinagjá in Mývatnsöræf on 18 February on a 25km (16mi) long fissure. It lasted until mid-August and flowed from Nýjahraun. It is believed to be a magma flow from Askja. (Part of the North volcanic zone (NVZ))
1875 - Askja One of the largest ash eruptions in Icelandic history began on March 28 and lasted for about eight hours. Eruption from Víti and other craters. Heavy damage from ash fall in the middle of East Iceland and many towns were deserted. Many East Fjord people moved to the West as a result. Öskjuvatn was formed and it grew steadily. Eruptions occurred for several months. (Part of the North volcanic zone (NVZ))
1918 - Katla. The eruption began on October 12 and ended on November 5 . The eruption reached a height of 14.3km (8.9mi) and caused considerable damage in Skaftártunga. There was a lot of lava flow on Mýrdalssandur. It extended the southern coast by 5km (3.1mi) due to laharic flood deposits. Its present dormancy is among the longest in known history.(Part of the East volcanic zone (EVZ))
1926 - at Eldey. Turbulence in the sea for several hours.
1927 - Esjufjöll. A small eruption, a lava flow off Breiðamerkurjökull and a Jökulhlaup (literally "glacial run") a type of glacial outburst flood). One person was killed. It is located at the SE part of the Vatnajökull icecap. (Part of the East volcanic zone (EVZ))
1930s - Gjálp An eruption took place in the 1930s. It had also caused a Jökulhlaup (literally "glacial run") a type of glacial outburst flood), but at the time, science could not yet analyze the events. The eruption remained subglacial.(Part of the East volcanic zone (EVZ))
1947- 48 - Hekla, eruption number 14 began on March 29 with an explosion. The plume reached a height of 30km (19mi) ash fall to the south over Fljótshlíð and Eyjafjöll. Heklugjá opened lengthwise, about 0.8km3 (0.19cumi) of lava flowed, mostly to the west and southwest from Axlargígur. (Part of the East volcanic zone (EVZ))
1963- 67 - Vestmannaeyjar: Surtsey rose from the sea on November 14 in an underwater eruption southwest of Geirfuglasker. Later, the islands Syrtlingur and Jólnir were formed but soon disappeared again.
1970 - Hekla, eruption number 15 began on May 5 in the southwestern part of Heklugjár and in Skjólkvíar north of the mountain. Considerable ash fall to NNV, all the way north to Húnavatnssýslur. In the mountain itself the activity stopped after a few days but in Skjólkvíar it erupted for about 2 months. (Part of the East volcanic zone (EVZ))
1973 - Eldfell, Westman Islands, VEI 3. A 1600 m long eruption fissure opens east of Heimaey on 23 January. About a third of the town was buried under lava, over 400 properties were destroyed. A volcano formed and Heimaey expanded to the east.
1975 - Krafla fires, 1st eruption 20 December. Lava eruption from a short fissure at Leirhnjúkur. Note: Mývatnseldar (is:Mývatnseldar), (Myvatn Fires, Krafla Fires), Lake Mývatn and the volcanic "Viti crater" (Hell crater) formed by Krafla.(Part of the North volcanic zone (NVZ))
1980- 81 - Hekla, eruption number 16 began on August 17 and lasted until the 20th . Ash spread to the north, lava flowed mostly to the west and north. The eruption resumed on April 9 of the following year and ended on April 16. (Part of the East volcanic zone (EVZ))
? 1985 - Final ridge under Vatnajökull. Possible eruption. Gosórói on meters and sigg boilers in the glacier.
1991 - Hekla, eruption number 17 began on January 17 in the southern part of Heklugjár but soon subsided. One crater east of the mountain was active until March 17. A considerable amount of lava flowed on the south side of the mountain, but there was little ash fall. (Part of the East volcanic zone (EVZ))
1996 - 1996 eruption of Gjálp (Gjálpargosið / Bárðarbunga). An eruption began on 30 September in a 4–5km (2.5–3.1mi) fissure under a glacier between Bárðarbunga and Grímsvatn and lasted until 13 October. The seismic activity indicated a magma flow from Bárðarbunga. Melting water flowed to Grímsvatn and ran from there to Skeiðarársandur on 5 November. (Part of the East volcanic zone (EVZ))
2014-15 - Holuhraun. The eruption began on August 29, 2014, and ended on February 28, 2015. (Part of the North volcanic zone (NVZ))
2021 - Fagradalsfjall. The eruption began in Geldingadalir valley on March 19 and the "Fagradalshraun" lava has since then flowed into Meradalir valley and Nátthagi valley. (Part of the Reykjanes volcanic zone (RVZ))
The Reykjanes volcanic zone (RVZ) is one of two major and active transform faults zones striking west-northwest in northern and southern Iceland. Two large fracture zones, associated with the transform faults, namely Tjörnes and Reykjanes Fracture Zones are found striking about 75°N to 80°W.
the Reykjanes Ridge (RR) (the Mid-Atlantic Ridge south of Iceland)
the Reykjanes Volcanic Belt (RVB) (on the main island)
The Tjörnes Fracture Zone (TFZ) connects the North Volcanic Zone to the Kolbeinsey Ridge (KR), which is part of the Mid-Atlantic Ridge. It contains its own volcanic systems, which are smaller than those in the Mid-Iceland Belt.
It is one of two major and active transform faults zones striking west-northwest in northern and southern Iceland. The Tjörnes and Reykjanes Fracture Zones are found striking about 75°N to 80°W.
Grímsvötn, including the Skaftá eruption of 1783, is probably the most eruptive volcano system. The Lakagígar lava field alone is estimated to have produced about 15 cubic kilometres (3.6cumi) of lava. Grímsvötn has probably had more than 30 eruptions in the last 400 years, and produced around 55 cubic kilometres (13cumi) over the last 10,000 years.(Part of the East volcanic zone (EVZ))
Katla has erupted 17 times in historical times, and Eldgjá seems to be part of the same system. The total volume of volcanic eruptions from Katla over the last 10,000 years is very similar to Grímsvötn.(Part of the East volcanic zone (EVZ))
Hekla has erupted at least 17 times in historical times, with total volume about 7 cubic kilometres (1.7cumi), but around 42 cubic kilometres (10cumi) since the last ice age.(Part of the East volcanic zone (EVZ))
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