Fagradalsfjall facts for kids

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Quick facts for kids Fagradalsfjall
Fagradalsfjall with its main peak Langhóll and Geldingadalir to the right (2012 photo)
Highest point
Elevation	Mountain: 385 m (1,263 ft)
Geography
Fagradalsfjall Location in Iceland
Geology
Mountain type	Tuya and fissure system
Last eruption	3–21 August 2022

Fagradalsfjall is a 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 Svartsengi and Krýsuvík systems. The highest summit in this area is Langhóll (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 may develop into 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. It is still considered ongoing, although there has been no visible activity since 21 August 2022.

Etymology
Tectonic setting
Risk mitigation and tourism
Supposed burial site
See also

Etymology

The name is a compound of the Icelandic words 'fagur' ("fair", "beautiful"), 'dalur' ("dale", "valley") and 'fjall' ("fell", "mountain"). The mountain massif is named after Fagridalur ( "fair dale" or "beautiful valley") which is at its northwest. The 2021 lava field is named Fagradalshraun.

Tectonic setting

The mountain Fagradalsfjall is a volcano in areas of eruptive fissures, cones and lava fields also named Fagradalsfjall. The Fagradalsfjall fissure swarm is 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. Other scientists propose that Fagradalsfjall could represent a separate volcanic system from Krýsuvík and it is regarded as such in some publications. It 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 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 6,342 years until an eruption fissure appeared in the area in March 2021.

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 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 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) that is linked to the Earth's mantle, and the lava flow may be determined by the properties of the eruption channel.

Risk mitigation and tourism

Due to the volcanic site's proximity to the town of Grindavik, Vogar and to a lesser extent Keflavik, Keflavik 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 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.

Air traffic

The eruption site is only around 20 km from Iceland's main international airport, Keflavik International Airport. Due to the eruption's effusive nature with little to no ash production, it 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 Keflavik 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 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.

Roads and utilities

The main concerns are if lava flows were to reach the main highway to Keflavik and the airport, Road 41, as well as the south coast road, Road 427, an important evacuation route for the town of Grindavik.

In addition, if the lava flows travel northwards, an important high-voltage transmission line to Keflavik 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 Keflavik. However, the fissure's location as of August 2022 is unlikey to affect the roads and utilities.

Within a week of the starts of the 2021 eruption, power and fiber-optic lines were laid from Grindavik 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.

Lava flow experiments

Lava levee constructed as an experiment in summer 2021 to control lava flows at the Fagradalsfjall volcano.

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 was conducted by constructing large levees to control direction of lava flows; they were moderately effective in controlling slow moving lava flows.

Tourism management

LB-SMS sent to mobile phones entering the vicinity of the volcano in August 2022.

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 from Reykjavík. Access is a short distance from Grindavik along paved Road 427, with limited parking available by the trailhead. Depending on the route taken, the hike to the new site is around 6–8 km 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.

Due to its easy access, a very large number of locals and tourists have visited the site. Around 10,000 people visited the 2022 eruption on its first day. Authorities have kept the site open for the most part, and try to inform rather than ban people from visiting the site. There have been no deaths reported as a result of the eruption, However, many injuries have been indirectly caused by the volcano, due to inadequately equipped tourists visiting the site with reports of broken ankles, lost travellers and hypothermia as weather is very unpredictable in the area.

Authorities have used Location Based SMS messages to inform and warn tourists travelling to the site to be prepared. The site is manned during busy periods by the volunteers from the Icelandic Association for Search and Rescue, as well as local police. The site has had to be evacuated at least once due to fast moving lava flows. The site was closed for 2 days from the 7th of August 2022 due to inclement weather, however groups of tourists who did not heed the closures had to be rescued by the local volunteer search and rescue team, Þorbjörn.

Supposed burial site

The area where the volcano first erupted is thought to be the ancient burial site of an early Norse settler Ísólfur frá Ísólfsstöðum. However, a quick archaeological survey of Geldingadalur after the eruption started found no evidence of human remains in the area.