A tuya is a flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet . They are rare worldwide, being confined to regions which were covered by glaciers and had active volcanism during the same period.
83-702: Fagradalsfjall ( Icelandic: [ˈfaɣraˌtalsˌfjatl̥] ) is an active tuya volcano formed in the Last Glacial Period on the Reykjanes Peninsula , around 40 kilometres (25 mi) from Reykjavík , Iceland. Fagradalsfjall is also the name for the wider volcanic system covering an area 5 kilometres (3 mi) wide and 16 kilometres (10 mi) long between the Eldvörp–Svartsengi [ˈɛltvœr̥p–ˈsvar̥(t)sˌeiɲcɪ] and Krýsuvík systems. The highest summit in this area
166-492: A geographer for the British Columbia government, described tuyas in the following way: Because they erupt under ice and water, tuyas have phreatomagmatic eruptions creating layers of breccia and hyaloclastite above pillow lavas . If the volcano breaches the surface of the glacier it will be topped by a subaerially erupted lava plateau . The origin of the term comes from Tuya Butte , one of many tuyas in
249-465: A magma chamber underneath, whose size and pressure on it determine the size and length of eruption. This eruption may be fed by a relatively narrow and long channel (~ 17 km (11 mi)) that is linked to the Earth's mantle , and the lava flow may be determined by the properties of the eruption channel. However, the channel may also be linked to a deep magma reservoir located near the boundary between
332-417: A shield volcano . Due to its relative ease of access from Reykjavík, the volcano has become an attraction for local people and foreign tourists. Another eruption, very similar to the 2021 eruption, began on 3 August 2022, and ceased on 21 August 2022. A third eruption appeared to the north of Fagradalsfjall near Litli-Hrútur [ˈlɪhtlɪ-ˌr̥uːtʏr̥] on 10 July 2023, and ended on 5 August 2023. The name
415-407: A depth of 17–20 kilometres (11–12 mi) from the Earth's mantle , and may be of a more primitive kind than those previously observed. The channel widened in the first six weeks leading to increased lava flow. The eruption may create a new shield volcano if it continues for long enough. The formation of such volcano has not been studied before in real time, and this eruption can offer insights into
498-415: A glacier cools very quickly and cannot travel far, it piles up into a steep-sided hill. If the eruption continues long enough, it either melts all the ice or emerges through the top of the ice and then creates normal-looking lava flows that make a flat cap on top of the hill. Discovering and dating the lava flows in a tuya has proven useful in reconstructing past glacial ice extents and thicknesses. Tuyas are
581-467: A large lava pond that traveled NW of the breached vent and occasionally, lava breakouts would be noted along the ponded lava. Each day during 12-16 August the primary eruptive cone continued to grow, evolving to a perched lava pond that fed the lava flows to the NW of it. The lava flow decreased around 17 August and stopped on 21 August 2022. An estimated 12 million cubic meters of lava had erupted. The lava near
664-571: A lesser extent Keflavík , Keflavík International Airport and the Greater Reykjavík Area , Iceland's Department of Civil Protection and Emergency Management has created protocols for evacuation plans of nearby settlements and in case of gas pollution and/or lava flows. The large number of tourists visiting the eruption sites is also a concern to authorities, especially under-equipped tourists and those who do not heed official closures during inclement weather or new lava flows. As of
747-417: A long period, then it can become stratified with lower density components rising to the top and denser materials sinking. Rocks accumulate in layers, forming a layered intrusion . Any subsequent eruption may produce distinctly layered deposits; for example, the deposits from the 79 AD eruption of Mount Vesuvius include a thick layer of white pumice from the upper portion of the magma chamber overlaid with
830-517: A new fissure , variously estimated to be between about 100 and 500 metres (300 and 2,000 ft) long, opened a distance of about 1 kilometre (0.6 mi) to the north/north-east of the still-active vents at the center of the March eruption. As a precaution the area was evacuated by the coast guard. Some time later, another eruption fissure opened parallel to the first on the slopes of Fagradalsfjall. The lava production of all open eruption fissures in
913-425: A pattern of many hours of inactivity, for example on 1 and 4 July, with the eruptions resuming later. Lava flow from the crater ceased for 4 days from 5 July until 9 July, when eruptions resumed, initially with a periodicity of around 10 to 15 minutes, then lengthening to 3 to 4 an hour by 13 July. Lava has also been observed emerging from the bottom of the volcano on 10 July with considerable amount of lava flowing into
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#1732779849464996-552: A pattern of mostly around 15 hours of inactivity alternating with around 20 hours of continuous eruption in August. It has been speculated that there are blockages at the top hundred metres of the eruption channel. By July, this eruption had become larger than most eruptions that have ever occurred on the Reykjanes peninsula. Measurement taken on 27 July indicated that the lava flow had increased again, returned to and possibly exceeding
1079-450: A relatively shallow level in the crust. However, the rate of magma production in tectonic settings that produce supervolcanoes is quite low, around 0.002 km year , so that accumulation of sufficient magma for a supereruption takes 10 to 10 years. This raises the question of why the buoyant silicic magma does not break through to the surface more frequently in relatively small eruptions. The combination of regional extension, which lowers
1162-434: A similar layer of grey pumice produced from material erupted later from lower in the chamber. Another effect of the cooling of the chamber is that the solidifying crystals will release the gas (primarily steam ) previously dissolved when they were liquid, causing the pressure in the chamber to rise, possibly sufficiently to produce an eruption. Additionally, the removal of the lower melting point components will tend to make
1245-470: A steady 12 m/s (420 cu ft/s), and the lava now covered an area of more than 3 km (1.2 sq mi) increasing by around 60,000 m/d (650,000 sq ft/d). Lava had accumulated 100 m (330 ft) deep around the volcano. The lava flow became continuous, which can be either above or below ground, although the eruptions also became calmer with the occasional increase in activity. There appeared to be no direct connection between
1328-929: A type of subglacial volcano that consists of nearly horizontal beds of lava capping outward-dipping beds of fragmental volcanic rocks, and they often rise in isolation above a surrounding plateau . Tuyas are found in Iceland , British Columbia , the Santiam Pass region in Oregon , the Tyva Republic in eastern Russia, the Antarctic Peninsula and beneath the West Antarctic Ice Sheet . Tuyas in Iceland are sometimes called table mountains because of their flat tops. S. Holland,
1411-415: A volcano may have a deep magma chamber many kilometers down, which supplies a shallower chamber near the summit. The location of magma chambers can be mapped using seismology : seismic waves from earthquakes move more slowly through liquid rock than solid, allowing measurements to pinpoint the regions of slow movement which identify magma chambers. As a volcano erupts, surrounding rock will collapse into
1494-702: A week of the start of the 2021 eruption, power and fiber-optic lines were laid from Grindavík to support operations of the authorities near the eruption site as well as 4G cell and TETRA masts were set up to ensure access to communications and emergency services ( 112 ) for tourists and authorities. In July 2021, in collaboration with Iceland's Department of Civil Protection and Emergency Management, utility companies conducted an experiment by burying various types of utilities ( underground electrical cables , fibers , water lines and sewage line) with varying levels of insulation in order to see how overland lava flows affect buried utilities. Another separate experiment
1577-626: Is Langhóll [ˈlauŋkˌhoutl̥] (385 m (1,263 ft)). No volcanic eruption had occurred for 815 years on the Reykjanes Peninsula until 19 March 2021 when a fissure vent appeared in Geldingadalir to the south of Fagradalsfjall mountain. The 2021 eruption was effusive and continued emitting fresh lava sporadically until 18 September 2021. The eruption was unique among the volcanoes monitored in Iceland so far and it has been suggested that it could develop into
1660-509: Is a volcano in areas of eruptive fissures, cones and lava fields also named Fagradalsfjall. The Fagradalsfjall fissure swarm was considered in some publications to be a branch or a secondary part of the Krýsuvík-Trölladyngja volcanic system on the Reykjanes Peninsula in southwest Iceland, but scientists now consider Fagradalsfjall to be a separate volcanic system from Krýsuvík and it is regarded as such in some publications. It
1743-532: Is a compound of the Icelandic words ' fagur ' (" fair ", "beautiful"), ' dalur ' (" dale ", "valley") and ' fjall ' (" fell ", "mountain"). The mountain massif is named after Fagridalur ( [ˈfaɣrɪˌtaːlʏr̥] , "fair dale" or "beautiful valley") which is at its northwest. The 2021 lava field is named Fagradalshraun [ˈfaɣraˌtalsˌr̥œyːn] . The mountain Fagradalsfjall
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#17327798494641826-531: Is also often used) to the south of Fagradalsfjall, the first known eruption on the peninsula in about 800 years. Fagradalsfjall had been dormant for 6,000 years. The eruptive activity was first announced by the Icelandic Meteorological Office at 21:40. Reports stated a 600–700-metre-long (2,000–2,300 ft) fissure vent began ejecting lava , which covered an area of less than 1 square kilometre (0.39 sq mi). As of
1909-516: Is in a zone of active rifting at the divergent boundary between the Eurasian and North American plates . Plate spreading at the Reykjanes peninsula is highly oblique and is characterized by a superposition of left-lateral shear and extension. The Krýsuvík volcanic system has been moderately active in the Holocene , with the most recent eruptive episode before the 21st century having occurred in
1992-434: Is not considered a risk to air traffic. The ICAO Aviation Colour code has mostly stayed orange (ongoing eruption with low to no ash production). This has meant that no interruptions to flight traffic to and from Keflavík International Airport. Icelandic Coast Guard helicopters have conducted many research and monitoring flights around the volcano as well as large numbers of helicopter tour companies operating and landing in
2075-426: Is observed in geysers where the frequency of eruption may be determined by the size of the reservoir below and how quickly it is filled up. The volcano was pulsing at a rate of around eight eruptions per hour on 14 September. No lava flowed out directly from the crater, instead lava began to emerge in significant amount from outside the volcano on 15 September. On 16 September 2021, after 181 days of eruption, it became
2158-468: Is unusual, as eruption outputs typically decrease with time. Scientists from the University of Iceland hypothesize that there is a large magma reservoir deep under the volcano, not the typical smaller magma chamber associated with these kinds of eruptions that empty over a short time. From the composition of the magma sampled, they also believe that there is a discrete vent feeding the main lava flow from
2241-412: The Reykjanes Peninsula including over 10,000 recorded earthquakes from 30 July to 3 August with two quakes measuring over 5.0 M w , another eruption began at Fagradalsfjall. A live stream from a camera at the site showed magma spewing from a narrow fissure vent . On 4 August the Icelandic Meteorological Office estimated it 360 m (1,180 ft) in length. Over 1,830 people visited the volcano on
2324-634: The 12th-century CE. The Fagradalsfjall mountain was formed from an eruption under the ice sheet in the Pleistocene period, and it had lain dormant for 6,000 years until an eruption fissure appeared in the area in March 2021. The wider peninsula had been dormant for nearly 800 years, since the end of the Reykjanes Fires in 1240. The unrest and eruption in Fagradalsfjall are part of a larger unrest period on Reykjanes Peninsula including unrest within several volcanic systems and among others also
2407-447: The 13 April and at each fissure, activity concentrated and formed individual vents. Towards the end of April, activity at most vents, apart from Vent 5, started to decrease. By 2 May 2021, only one fissure, Vent 5 that appeared near the initial eruption site on Geldingadalir, remained active. It developed into a volcano with the occasional explosive eruptions within its crater that sometimes reached heights of hundreds of meters. The rim of
2490-402: The 21st century. The volcano stopped erupting on 2 September, but lava flow resumed on 11 September, with the magma breaking through the lava field surface in several places. However, the main crater channel appeared to have been blocked, and the crater was filled with lava from a source underneath the northwestern wall through a crack on the wall, and lava also flowed outside the volcano through
2573-570: The Capital region, and as far as Borgarnes. Several of these earthquakes were above an M w 3, with the largest event of an M w 4 occurring at 1403. according to the Icelandic Meteorological Office's automatic location system; an M w 5.4 event was detected at 1748. Deformation models indicated magma was around 1 km below the surface at 1749 on 2 August, according to IMO. On 3 August 2022, after weeks of unrest on
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2656-463: The Geldingadalur fissures and the ones on the slope of the mountain. Search and rescue crews observed a new depression, about 1 m (3 ft) deep there the previous day. The lava from this fissure flowed into Geldingadalur valley. Another fissure opened during the night of 10–11 April 2021 between the two open fissures on the slopes of Fagradalsfjall. In total, 6 fissures had opened until
2739-425: The March eruptions, the lava flows posed no threat to residents, as the area is mostly uninhabited. The eruption has been called Geldingadalsgos ( [ˈcɛltiŋkaˌtalsˌkɔːs] "Geldingadalur eruption"). On 26 March, the main eruptive vent was at 63.8889 N, 22.2704 W , on the site of a previous eruptive mound. The eruption may be a shield volcano eruption , which may last for several years. It could be seen from
2822-584: The Meradalir valleys, and a section of the volcano on the northeastern side also broke off on 14 July. Lava flow was estimated to be around 10 m/s (350 cu ft/s) but averaged to 5 to 6 m/s (180 to 210 cu ft/s) due to the periods of inactivity from late June to mid-July, half of the flow rate in May and June. The periodic lull in activity continued, with 7 to 13 hours of inactivity and similar period of eruption by late July, which lengthened to
2905-423: The activity at the crater and lava flow. The lava flow can be tracked by helicopter or satellite, for example via radar imaging that can penetrate through the clouds and volcanic smog that had become more frequent in the area by July. The eruptions stayed unusually constant until 23 June, and the activity then reduced significantly on 28 June, becoming inactive for many hours, and resuming on 29 June. It shifted to
2988-666: The alert level was lowered from "Orange" to "Yellow" due to no lava having erupted since 18 September. The Icelandic Meteorological Office also stated that "it is assessed that Krýsuvík volcano is currently in a non-eruptive state. The activity might escalate again, so the situation is monitored closely". On 30 July, IMO reported an intense earthquake swarm in an area close to the lava field in Geldingadalur. On 31 July, almost 3,000 earthquakes were detected. Earthquakes were reportedly felt in SW Iceland, in Reykjanesbær, Grindavík,
3071-564: The area of the Tuya River and Tuya Range in far northern British Columbia , Canada . While still in graduate school in 1947, Canadian geologist Bill Mathews published a paper titled, "Tuyas, Flat-Topped Volcanoes in Northern British Columbia", in which he coined the term "tuya" to refer to these distinctive volcanic formations. Tuya Butte is a near-ideal specimen of the type, the first such landform analyzed in
3154-494: The crust and the mantle. Some scientists believed that volcanic activities in the area may last for decades. Beginning December 2019 and into March 2021, a swarm of earthquakes , two of which reached magnitude M w 5.6, rocked the Reykjanes peninsula , sparking concerns that an eruption was imminent, because the earthquakes were thought to have been triggered by dyke intrusions and magma movements under
3237-470: The crust because it is less dense than the surrounding rock. When the magma cannot find a path upwards it pools into a magma chamber. These chambers are commonly built up over time, by successive horizontal or vertical magma injections. The influx of new magma causes reaction of pre-existing crystals and the pressure in the chamber to increase. The residing magma starts to cool, with the higher melting point components such as olivine crystallizing out of
3320-427: The discharge rate of the lava at about 9 m (320 cu ft) per second, which is nearly double the drop in the rate. As of 31 July, the outpouring lava has covered an area of 1.5 km (0.58 sq mi) per second with a volume of approximately 15.9 million m (560 million cu ft). Lava flow reduced to 3–4 m (110–140 cu ft) per second by early August, suggesting that
3403-464: The electricity network. The Fagradalsfjall volcano site is unusual in terms of its close proximity to Iceland's main international airport and popular tourist sites such as the Blue Lagoon . The site is only around 60 km (37 mi) from Reykjavík . Access is a short distance from Grindavík along paved Road 427, with limited parking available by the trailhead. Depending on the route taken,
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3486-442: The end of the first eruption and the lava of the second eruption, indicating a link to the previous two eruptions. The latest Icelandic Institute of Earth Sciences statistics revealed on 31 July indicate a notable reduction of the effusive eruption. The estimated lava flow discharge rate during 23-31 July was measured to be about 5 m (180 cu ft) per second. The previous values, detected between 18 and 23 July, signalized
3569-419: The eruption is approaching its end. With the reduced amount of lava in the crater, a smaller cone also formed within the crater. Volcanic activity at the site ceased on 5 August 2023. The eruption site proved very popular with tourists once more. An estimated 700,000 people have visited the area since the 2021 Fagradalsfjall eruption. Due to the volcanic site's proximity to the town of Grindavík , Vogar and to
3652-457: The eruption shows a composition differing from historical Reykjanes lavas. This could be caused by a new batch of magma arriving from a large magma reservoir at a depth of about 17–20 km (11–12 mi) at the Moho under Reykjanes. Results from measurements published by University of Iceland on 26 April 2021 showed that the composition of eruption products had changed, to more closely resemble
3735-494: The eruption. Iceland's main airport, Keflavík Airport , was briefly on alert, which is a standard procedure during eruptions, though the facility did not cancel any flights. Airplanes were prohibited from flying over the site, although some helicopters were sent in to survey the eruption. The eruption was not producing large plumes, though it was likely to affect air quality and pollution in immediately surrounding areas. Professor of geophysics Magnús Tumi Guðmundsson said, judging from
3818-714: The first day. It erupted over a lava flow from the 2021 eruption. The Icelandic Meteorological Office initially advised people not to go near Fagradalsfjall due to the new eruption. Lava flows were reported traveling downslope to the NW. The flow rate was about 32 m/s (1,100 cu ft/s) during the initial hours of the eruption, which then decreased to an average of 18 m/s (640 cu ft/s) from 1700 on 3 August until 1100 on 4 August. By this time, about 1.6 million cubic meters of lava had covered an area of 0.14 km (0.054 sq mi). Iceland's Department of Civil Protection and Emergency Management stated that no lives or infrastructure were currently at risk from
3901-637: The geological literature, and this name has since become standard worldwide among volcanologists in referring to and writing about these formations. Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies north of Tuya Lake and south of the Jennings River near the boundary with Yukon . Around the same time that Mathews published his paper, the Icelandic geologist Guðmundur Kjartansson had distinguished between "móberg" ridges and tuyas in Iceland and proposed
3984-406: The highest one measured at 460 m (1,510 ft). The lava jets have been explained as explosive release of ancient trapped water or magma coming in contact with groundwater. The lava flow rate in the following weeks was also double that of the average for the first six weeks, with an average lava flow rate of 12.4 m/s (440 cu ft/s) from 18 May to 2 June. The increase in lava flow
4067-463: The hike to the new site is around 6–8 km (3.7–5.0 mi) each way, taking around 3–6 hours in hiking time (not including sightseeing or stops). Many parts of the route are extremely steep with uneven rocky ground, as well as being poorly signed due to the recency of the eruption. Depending on the wind direction, toxic gas pollution can be a risk as well as unpredictable lava flows and new fissures opening up. Tuya As lava that erupts under
4150-452: The hypothesis that they were formed during subglacial and intraglacial eruptions. The term tuya may be derived from a Tahltan word. Antarctica : Canada : United States : Iceland : Tuva Republic : Magma chamber A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma , in such a chamber is less dense than
4233-440: The initial lava flow, that the eruption was likely five to ten times bigger than the 2021 eruption, but that it was not "the big one". From the nearby geomorphology , the lava was likely to flow into the Meradalir valleys. According to a news article from RUV, the length of the active fissure had decreased and the middle part of the fissure was the most active by 5 August. In addition, the number of daily earthquakes declined around
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#17327798494644316-404: The lava by then flowing to the east. Lava flow also reached a volume of 12.4 million m (440 million cu ft), greater in volume than the second eruption, covering an area of 1.2 km (0.46 sq mi). By 23 July, lava flow activity was occurring entirely beneath the surface. The lava since the beginning of the eruption has been determined to be similar to the lava from
4399-477: The lava flows travel northwards, an important high-voltage transmission line to Keflavík is in danger of being cut off. Communications fiber routes both to the north and south side of the volcano are also in danger of being cut off, which could impact communications and the data center industry in Keflavík. However, the fissure's location as of August 2022 is unlikely to affect the roads and utilities. Within
4482-405: The longest eruption of the 21st century in Iceland. Average lava flow was 16 m/s (570 cu ft/s) from 11 to 17 September when flow resumed, with the lava field increasing to 151 million m (5.3 billion cu ft) covering an area of 4.8 km (1.9 sq mi). The eruption stopped again on 18 September, but the activity decreased unusually slowly. On 18 October,
4565-457: The magma more viscous (by increasing the concentration of silicates ). Thus, stratification of a magma chamber may result in an increase in the amount of gas within the magma near the top of the chamber, and also make this magma more viscous, potentially leading to a more explosive eruption than would be the case had the chamber not become stratified. Supervolcano eruptions are possible only when an extraordinarily large magma chamber forms at
4648-445: The main trail that provide access to the main viewing area on Gónhóll, first on 4 June, then again early in the morning of 13 June at another location. A further wall five meters high and 200 meters long was then created on 15 June in an attempt to divert lava flow away from Nátthagakriki [ˈnauhtˌhaːɣaˌkʰrɪːcɪ] with important infrastructure to its west and north. A barrier of 3 to 5 m high started to be constructed on 25 June at
4731-467: The maximum attainable overpressure on the chamber roof, and a large magma chamber with warm walls, which has a high effective viscoelasticity , may suppress rhyolite dike formation and allow such large chambers to fill with magma. If the magma is not vented to the surface in a volcanic eruption, it will slowly cool and crystallize at depth to form an intrusive igneous body, one, for example, composed of granite or gabbro (see also pluton ). Often,
4814-401: The mouth of Nátthagi to delay the flow of the lava over the southern coastal road and properties on Ísólfsskáli [ˈiːsˌoul(f)sˌskauːlɪ] , although it was expected that the lava would eventually flow over the area into the sea. A proposal to build a bridge over the road to allow the lava flow underneath was rejected. Around three months after the volcano first erupted, the lava flow was
4897-480: The older lava field of Meradalir, but the lava caused significant wildfires in the area. Some lava flowed in different directions when the wall of the volcano collapsed on 19 July, but it then resumed flowing southwards. The crater rim has widened significantly, which increased the possibility of wall collapse, and another rim collapse happened on 24 July. Lava flow gradually slowly fall through time, down to 8 m (280 cu ft) per second by 23 July, with most of
4980-525: The peak level last seen in June. The measurement indicated an average flow of 17–18 m/s (600–640 cu ft/s) over 8–10 days, the highest observed thus far, but with a large margin of error. After a couple of months where the lava flowed mainly into the Meradalir valleys, the lava started to flow down the Nátthagi valley again on 21 August. The eruption by now had become the second longest in Iceland of
5063-411: The peninsula. Minor damage to homes from a 4 February 2021 magnitude 5.7 earthquake was reported. In the three weeks before the eruption, more than 40,000 tremors were recorded by seismographs. On 19 March 2021, an effusive eruption started at approximately 20:45 local time in Geldingadalir ( [ˈcɛltiŋkaˌtaːlɪr̥] ; the singular "Geldingadalur" [ˈcɛltiŋkaˌtaːlʏr̥]
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#17327798494645146-442: The same day; strong gas-and-steam emissions were still visible. By 10 August lava was primarily erupting from a central cone and flowed ESE and NW. IMO reported that lava was mostly flowing onto the 2021 lava flow field and was filling the eastern end of the Meradalir lava through at least 16 August. There were three vents within the building cone that were visible on 10 August: the first is the largest and most centrally located vent,
5229-563: The same time, and was producing lava fountains up to 50 m (160 ft) in height on Sunday, 25 April 2021. On 28 April 2021, the lava fountains from the main crater reached a height of 250 m (820 ft). The eruption pattern changed on 2 May from a continuous eruption and lava flow to a pulsating one, where periods of eruptions alternated with periods of inactivity, with each cycle lasting 10 minutes to half an hour. The magma jets became stronger, producing lava fountains of 300 m (980 ft) in height, visible from Reykjavík , with
5312-429: The second eruption in 2022, there is little risk of lava flows blocking roads or reaching settlements, but this could change if the Meradalir valleys fill with lava or another fissure opens up in a different area. The eruption site is only around 20 km (12 mi) from Iceland's main international airport, Keflavík International Airport . Due to the eruption's effusive nature with little to no ash production, it
5395-430: The second is to the left (east) of the central vent, and the third is the smallest one located to the right (west) of the central vent. Each of these vents erupted strong lava fountains rising tens to several tens of meters high during at least 10-13 August, then during 14-16 August the height of the lava fountains diminished. A smaller, secondary cone formed to the east of the main cone around 12 August. These vents fed into
5478-434: The second phase also lasted around two weeks with new eruptions to the north of the first crater with variable lava flow of 5–8 m/s (180–280 cu ft/s). This is followed by a period of two and a half months of eruption at a single crater with largely continuous and sometimes pulsating eruption and lava flow of around 12 m/s (420 cu ft/s) lasting until the end of June. From then on until early September
5561-405: The solution, particularly near to the cooler walls of the chamber, and forming a denser conglomerate of minerals which sinks (cumulative rock). Upon cooling, new mineral phases saturate and the rock type changes (e.g. fractional crystallization ), typically forming (1) gabbro , diorite , tonalite and granite or (2) gabbro , diorite , syenite and granite . If magma resides in a chamber for
5644-415: The suburbs of the capital city of Reykjavík and had attracted a large number of visitors. However, high levels of volcanic gases such as carbon dioxide and carbon monoxide made parts of the area inaccessible. On 13 April 2021, four new craters formed in Geldingadalir within the lava flows. The lava output which had been somewhat reduced over the last days, increased again. Around noon on 5 April 2021,
5727-483: The surrounding country rock , which produces buoyant forces on the magma that tend to drive it upwards. If the magma finds a path to the surface, then the result will be a volcanic eruption ; consequently, many volcanoes are situated over magma chambers. These chambers are hard to detect deep within the Earth, and therefore most of those known are close to the surface, commonly between 1 km and 10 km down. Magma rises through cracks from beneath and across
5810-414: The suspicion that more rarely, mid-ocean ridge eruptions may be supplied from levels deeper than 7 km (4.3 mi), as the near real time lava sampling prevented later lavas confusing the time sequence of the change in composition. Mixing in the magma reservoir happenned in a timescale of weeks, and it was replenished with new deeper melt within 20 days. The eruption itself also changed in character at
5893-422: The typical Holocene basalts of Reykjanes peninsula. The full study of the lava sample sequence confirmed that at the start of the eruption shallowest mantle sources dominated the melt but over the next three weeks magma was sourced from a greater depth from a near-Moho reservoir and rapidly rose to the surface. While it was known that most mid-ocean ridge (MOR) basalts result from crustal reservoir melts this proved
5976-418: The unrest at Þorbjörn volcano next to Svartsengi and the Blue Lagoon during the spring of 2020. However, eruptions at this location were unexpected as other nearby systems on the Reykjanes Peninsula had been more active. The 2021 eruption is the first to be observed on this branch of the plate boundary in Reykjanes. It appears to be different from most eruptions observed where the main volcanoes are fed by
6059-428: The vent was 20-40 m thick, but flows were 5-15 m thick in the Meradalir valley, outside the crater area Since then, there has been no visible activity at this site. Seismic activity in the area increased greatly starting 4 July 2023 with over 12,000 earthquakes recorded, and following a 5.2 magnitude earthquake, lava broke through the surface on 10 July 2023 near Litli-Hrútur northeast of previous eruptions. This eruption
6142-406: The vicinity, as well as small private aviation and sightseeing fixed wing aircraft circling the eruption site. Many unmanned drones are also active around the volcano site. The main concerns are if lava flows were to reach the main highway to Keflavík and the airport, Road 41 , as well as the south coast road, Road 427, an important evacuation route for the town of Grindavík . In addition, if
6225-526: The volcano itself had risen to a height of 334 m (1,096 ft) above sea level by September 2021. The lava flowed into the Meradalir valleys, and later the Nátthagi [ˈnauhtˌhaijɪ] valley. A number of smaller openings appeared temporarily, one small vent was reported to have erupted near the main crater on 1 July. On 14 August, lava spurted from what appeared to be a hole on the crater wall, and this turned out to be an independent eruption. Cracks appeared on Gónhóll [ˈkouːnˌhoutl̥] that
6308-461: The wall. The average lava flow over the past 32 days had returned to 8.5 m/s (300 cu ft/s), and the lava field of 143 million m (5.0 billion cu ft) now covered an area of 4.6 km (1.8 sq mi). After a period of continuous eruption, a pulsing pattern of activity last seen in April/May started on 13 September, a pattern believed to be similar to what
6391-423: The whole was estimated on 5 April 2021, being around 10 m/s (350 cu ft/s) and is flowing into the Meradalir valleys ( [ˈmɛːraˌtaːlɪr̥] , "mare dales") via a steep gully. About 36 hours later, around midnight on 6–7 April, another eruption fissure opened up. It is about 150 m (490 ft) long and about 400–450 m (1,300–1,500 ft) to the north-east of the first fissure, between
6474-430: The working of the magmatic systems. Two defensive barriers were created starting 14 May as an experiment to stop lava flowing into the Nátthagi valley where telecommunication cables are buried, and further on to the southern coastal road Suðurlandsvegur . However, the lava soon flowed over the top of eastern barrier 22 May, and cascaded down to the Nátthagi. Lava flowed over the western barrier on 5 June. Lava flow blocked
6557-651: Was a phase of fluctuating eruption with periodic strong lava flow interrupted by periods of inactivity. On 12 April, scientists from the University of Iceland measured the lava field's area to be 0.75 km (0.29 sq mi) and its volume to be 10.3 million m (360 million cu ft). The flow rate of the lava was 4.7 m/s (170 cu ft/s), and sulfur dioxide , carbon dioxide and hydrogen fluoride were being emitted at 6,000, 3,000 and 8 tonnes per day (5,900, 3,000 and 7.9 long tons per day) respectively. The lava produced by
6640-490: Was conducted by constructing large levees to control direction of lava flows; they were moderately effective in controlling slow moving lava flows. In July 2023, during the Litli-Hrútur eruption, Icelandic electrical grid operator Landsnet constructed a dummy electricity pole and installed a high voltage underground electrical cable in the path of lava, as an experiment to study the lava flow's potential effects on
6723-405: Was initially significantly stronger than the first two, with initial lava flow estimated to be 10 times more than the first eruption. Multiple eruptive fissures, originally 200 m (660 ft) in length, stretched for over 1 km (0.62 mi) between Fagradalsfjall and Keilir , significantly longer than the Meradalir eruptions. Flow of lava up to 50 m (1,800 cu ft) per second
6806-436: Was once popular with spectators in August but no lava flowed at the site. After eight and a half days of inactivity at the main volcano, lava broke through the surface in the lava field to the north of the crater in a number of places. The eruption showed distinct phases in its eruption pattern. The first phase lasted for about two weeks with continuous lava flow of around 6 m/s (210 cu ft/s) from its first crater,
6889-406: Was reported in the first day, but dropped to an average of 13 m (460 cu ft) per second, the peak flow rate of the first eruption, within a few days. The eruptions quickly reduced to a single 200 m (660 ft) long fissure, which formed a single elongated active cone that increased in height by around 3 m (9.8 ft) a day. The lava flowed in a southerly direction to meet
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