Most Recent Weekly Report: 22 November-28 November 2023 Cite this Report

On 22 November the Icelandic Meteorological Office (IMO) lowered the Aviation Color Code for Reykjanes to Yellow (the second level on a four-color scale), noting that seismicity associated with the magmatic dike intrusion had decreased during the previous week. Although inflation continued to be detected at Svartsengi, they determined that the likelihood of an eruption had decreased. During 22-27 November seismic activity was relatively stable at a rate of about 500 earthquakes per day, with most events concentrated near Sýlingarfell and Hagafell. Sometimes around midnight on 27 November an hour-long seismic swarm occurred in the vicinity of Sýlingarfell. A total of 170 earthquakes were recorded and located at depths of 3-5 km; the largest event was an M 3. Seismicity slowly decreased during 28-29 November and most of the events were small, below M 1. The rate of deformation also declined, though uplift at Svartsengi continued at around 1 cm per day. The seismic and deformation data suggested that magma continued to flow into the middle portion of the dike.

Source: Icelandic Meteorological Office (IMO)

Weekly Reports - Index

2023: October | November
2022: May | June
2020: January | February | March | April | June | October

22 November-28 November 2023 Cite this Report

On 22 November the Icelandic Meteorological Office (IMO) lowered the Aviation Color Code for Reykjanes to Yellow (the second level on a four-color scale), noting that seismicity associated with the magmatic dike intrusion had decreased during the previous week. Although inflation continued to be detected at Svartsengi, they determined that the likelihood of an eruption had decreased. During 22-27 November seismic activity was relatively stable at a rate of about 500 earthquakes per day, with most events concentrated near Sýlingarfell and Hagafell. Sometimes around midnight on 27 November an hour-long seismic swarm occurred in the vicinity of Sýlingarfell. A total of 170 earthquakes were recorded and located at depths of 3-5 km; the largest event was an M 3. Seismicity slowly decreased during 28-29 November and most of the events were small, below M 1. The rate of deformation also declined, though uplift at Svartsengi continued at around 1 cm per day. The seismic and deformation data suggested that magma continued to flow into the middle portion of the dike.

Source: Icelandic Meteorological Office (IMO)

15 November-21 November 2023 Cite this Report

Icelandic Meteorological Office (IMO) reported that intense seismicity and deformation at the Reykjanes volcanic system, caused by a magmatic dike intrusion with no surface eruption, was ongoing during 15-21 November. Seismicity during the week was relatively stable with 1,500-2,000 daily earthquakes; the number of events decreased during 20-21 November with only 165 recorded during 0000-1530. Earthquakes were mostly located at depths averaging 4 km.

Most of the earthquakes were located near the middle of the dike, near Hagafell, 3.5 km NNE of Grindavík, and near Sundhnúk, about 1 km NE of Hagafell and about 2 km ENE of Mt. Thorbjorn. Most earthquakes were less than M 2 during 15-16 November and less than M 1 during 16-17 November; the largest event during the week was an M 3 recorded on 17 November. On 16 November sulfur dioxide gas was measured from a borehole located at Svartsengi, N of Mt. Thorbjorn, and extended E to a notable depth. The presence of sulfur dioxide was another indication of the magma intrusion N of Hagafell. In addition to earthquake detected by the seismic network, new technology using the high-sensitivity fiber optic cable that runs from Svartsengi, W of Mt. Thorbjorn, to Arfadalsvík was also collecting seismic data.

Deformation data was consistent with magma flowing into the dyke at depths greater than 5 km. On 17 November GPS data from instruments in and around Grindavík, near the center of the subsidence zone, indicated about 3-4 cm of subsidence per day. Analysis of COSMO-SkyMed radar interferogram data from 18-19 November showed that 30 mm of uplift was centered in the vicinity of Svartsengi, about 2 km N of Hagafell. Uplift was recorded in that same area before the 10 November magmatic intrusion, thought the rate had accelerated. The uplift aligned with the margins of the intrusion, whereas subsidence was located above the intrusion itself. The deformation and seismic data indicated that Hagafell, where the intrusion was modeled to be the widest, was the most likely location for an eruption.

The Blue Lagoon geothermal pool was closed on 9 November and planned to remain closed at least until 30 November. Residents of Grindavík evacuated on 10 November, due to the uncertainty of an eruption and the onset of ground cracking and damaged infrastructure; access to the town continued to be restricted with only periodic entry allowed for residents to collect belongings. During the week ground cracks and sinkholes opened in and around Grindavík, affecting streets and buildings. Construction of earthen barriers began by 15 November to protect the Svartsengi power station, which supplies tens of thousands of people with electricity and hot water; new wells were being drilled to produce a back-up water supply. An 18 November news report indicated that most of the houses in Grindavík were undamaged, but some had been damaged along a big crack that goes through the town; a few homes were destroyed.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Almannavarnadeild ríkislögreglustjóra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management); mbl.is

8 November-14 November 2023 Cite this Report

The Icelandic Meteorological Office (IMO) reported increased seismic activity and deformation caused by a magmatic dike intrusion with no surface eruption through 14 November in the eastern Reykjanes-Svartsengi volcanic system on the Reykjanes Peninsula, W of the Fagradalsfjall fissure system that produced lava flows during eruptions over the previous three years. Due to increased local seismicity recorded since 25 October, the onset of ground inflation on 27 October, geophysical models of the magma intrusion, and uncertainties associated with a possible eruption site, the National Police Commissioner evacuated approximately 4,000 residents from the coastal town of Grindavík on 10 November. IMO is responsible for volcano monitoring in Iceland, in coordination with scientists from the University of Iceland, and the Department of Civil Protection and Emergency Management.

An intense seismic swarm occurred during the night of 8-9 November; seven earthquakes (max. M 4.0) were centered in the area from Eldvörp to E of Sýlingarfell, with the largest measuring M 4.8 at 0046 on the 9th located W of Mt. Þorbjörn. Ground uplift continued to be detected in GPS and satellite data, with the highest rates occurring NW of Þorbjörn. Geophysical models estimated the depth to the top of the intrusion was estimated to be ~800 m. On 10 November an intense seismic swarm at a depth of 5 km began near Sundhnjúkagigar, NE of Þorbjörn, around 0700 and increased further at 1500. More than 800 earthquakes were detected on 11 November at depths of 3-3.5 km and seismic activity migrated S towards Grindavík. IMO attributed the shallow seismicity to the intrusion extending from Stóra-Skógsfell, ~6 km NNE of Grindavík, to beneath Grindavík, and offshore. Data acquired from satellite radar showed a graben-like are of deflation cutting through Grindavík. Analysis of COSMO-SkyMed (CSK) radar interferogram data from 3-11 November indicated that the intrusion was about 15 km long at a minimum depth of less than 1 km.

Geodetic models on 12 November showed that an area of inflation was located 3.5 km N of Grindavík, close to Sundhnúkur. Approximately 1,000 earthquakes, less than M 3.0, were detected N of Grindavík at 3-5 km depths between 0000 and 1230 on 12 November. On 13 November, the size and intensity of earthquakes decreased, when approximately 900 earthquakes were detected at depths of 2-5 km between 0000 and 1620 in the area between Sundhnúkur and Grindavík. During 12-13 November, calculations estimated that the magma inflow to the intrusion was 75 cubic meters per second. Between 0000 and 1240 on 14 November, 700 earthquakes occurred at depths of 3-5 km along the intrusion; the largest was M 3.1. After IMO installed two Differential Optical Absorption Spectrometers (DOAS, remote sensing gas instruments) on Húsafell, one of them detected SO2 at the graben-like feature between Sundhnúkagígar and Grindavík, but the source was unknown. Additional GPS stations have also been installed to monitor deformation.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV); Almannavarnadeild ríkislögreglustjóra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management)

1 November-7 November 2023 Cite this Report

IMO reported that increased seismicity and deformation at the Reykjanes Peninsula were ongoing during 1-7 November and indicated magma accumulation at depths of 4-5 km in an area NW of Mt. Thorbjorn. A total of 7 cm of uplift was recorded in satellite data and by the Global Navigation Satellite System (GNSS) station near Mt. Thorbjorn during 27 October-6 November. The rate of inflation was fairly constant though it began to accelerate on 3 November. Data models indicated that the volume change associated with the uplift was double that of the four previous inflation events recorded during 2020-2022; the inflow of magma was estimated at 7 cubic meters per second, or four times greater than the highest inflow rate recorded during the previous events.

Intense seismicity continued. Over 10,500 earthquakes were detected during 25 October-1 November, out of which more than 26 exceeded M 3 and the largest was a M 4.5 recorded at 0818 on 25 October. Seismicity increased for early on 3 November, and then notably decreased around 1730. The signals were located along previously known faults, aligned in a N-S direction W of Mt. Thorbjorn. There was no indication of magma migrating to the surface. During 4-7 November there were around 2,200 earthquakes, which were located between Mt. Thorbjorn and Sýlingafell during 6-7 November.

Source: Icelandic Meteorological Office (IMO)

25 October-31 October 2023 Cite this Report

IMO reported that an intense earthquake swarm on the Reykjanes Peninsula began on 24 October. By 1700 on 26 October more than 4,000 earthquakes had been located at depths of 2-6 km. A total of 14 earthquakes had a magnitude over M 3; the largest event, a M 4.5, was recorded at 0818 on 25 October. Most of the activity occurred between Stóra-Skogafell and an area NE of Eldvörp. No ground deformation was recorded, though a single GPS station (FEFC), E of Festarfjall, recorded localized movement to the SE. During 25-26 October the displacement recorded by the FEFC station totaled about 2 cm and movement was also detected at a station in Selatangar. The swarm continued and by 1400 on 27 October more than 5,800 earthquakes had been recorded; a M 4 earthquake occurred at 0402 on 27 October and was located about 2 km N of Grindavík.

Seismicity decreased considerably by 1330 on 28 October, though the swarm was ongoing with a total of more than 7,000 earthquakes. Uplift centered around Svartsengi, 1.5 km NW of Mt. Thorbjorn, was clearly evident in satellite radar and GPS data. The uplift had begun at some point the previous day and likely signified a magmatic intrusion at depth. IMO raised the Aviation Color Code for Reykjanes to Yellow (the second level on a four-color scale) at 1518 on 28 October. During 1130 on 29 October to 1130 on 30 October about 1,300 earthquakes occurred at depths of 2-4 km. The largest event was a M 2.7 at 1140 on 29 October. Uplift continued during 28-31 October, though the rates began to decrease. Modeling suggested that magma was accumulating at a depth of about 4 km. An earthquake swarm began at 0840 on 31 October and lasted about two hours. The events were located at depths of 1.5-5 km and indicted that magma was moving.

Source: Icelandic Meteorological Office (IMO)

1 June-7 June 2022 Cite this Report

On 2 June IMO reported that the rate of uplift on the Reykjanes Peninsula had significantly decreased, and seismicity had been declining, with only about 150 earthquakes recorded the previous day. The Aviation Color Code was lowered to Green because the data indicated no magma movement.

Source: Icelandic Meteorological Office (IMO)

18 May-24 May 2022 Cite this Report

IMO reported an ongoing seismic swarm and uplift on the Reykjanes Peninsula, indicative of a magma intrusion. Satellite data analysis indicated that 4-4.5 cm of uplift occurred during 27 April-21 May centered just NW of Mt. Thorbjorn. Magma was accumulating at depths of 4-5 km, and the intrusion was possibly 7-8 km long. During 22-23 May about 400 earthquakes were recorded; a M 3 earthquake was recorded at 1113 on 22 May and a M 3.5 earthquake was recorded at 0715 on 23 May, both were located about 3 km E of Mt. Thorbjorn. The Aviation Color Code for Reykjanes remained at Yellow.

Sources: Icelandic Meteorological Office (IMO); Icelandic National Broadcasting Service (RUV)

11 May-17 May 2022 Cite this Report

The National Commissioner of the Icelandic Police declared a level of “uncertainty” for the Reykjanes Peninsula on 15 May, noting that the declaration meant that responders and agencies were to review their preparedness plans in response to recent increases in seismicity and deformation. IMO raised the Aviation Color Code for Reykjanes to Yellow on 16 May, stating that more than 3,000 earthquakes had been detected near Eldvörp in the Reykjanes/Svartsengi volcanic system during the past week. Nine earthquakes above M 3 and two earthquakes above M 4 were recorded during 15-16 May; the largest event was a M 4.3 which was recorded at 1738 on 15 May. The earthquakes were located at depths of 4-6 km. GPS and InSAR data detected inflation W of Thorbjörn during the previous two weeks, likely caused by a magmatic intrusion at 4-5 km depth.

Sources: Icelandic Meteorological Office (IMO); Almannavarnadeild ríkislögreglustjóra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management)

21 October-27 October 2020 Cite this Report

IMO reported that a M 5.6 earthquake was recorded at 1343 on 20 October beneath Nupshlidarhals, a hill about 5 km W of the geothermal area in Seltun. This was the largest earthquake since 2003 recorded in the Reykjanes peninsula. There were about 1,700 aftershocks recorded in the following 24-hour period. IMO received reports of rockfalls in steep areas and increased gas odors in the vicinity of Graenavatn at Nupshlidarhals. Four landslides were noted near the epicenter; some existing ground cracks were displaced and new cracks had formed in Krysuvikurbjarg. On 26 October IMO stated that seismic activity had significantly decreased in recent days; about 180 earthquakes below M 2.2 had been detected during the previous two days.

Source: Icelandic Meteorological Office (IMO)

10 June-16 June 2020 Cite this Report

IMO reported that a third injection of magma since the beginning of the year was occurring beneath the Reykjanes peninsula. Data suggested that the current inflationary period began in mid-May, though earthquake activity did not increase until around 30 May. During 30 May-15 June the seismic network recorded more than 2,000 events, with the largest, an M 3.4, recorded on 13 June. The intrusion was located about 1 km W of Thorbjorn at a depth of 3-4 km, and had an estimated volume of about 1.2 million cubic meters. This third intrusion was similar to the previous two intrusions, characterized as a sill that was a few hundred meters wide and about 6 km long. In total about 12 cm of uplift has been recorded since January. The Svartsengi geothermal plant noted no chemical changes in the geothermal system, though measurements showed increased fluid flow in the rocks within the system, along with the opening of old cracks and the formation of new ones.

Source: Icelandic Meteorological Office (IMO)

29 April-5 May 2020 Cite this Report

IMO reported that uplift detected in the Thorbjorn area decreased in the beginning of April and stopped later in the month. Seismicity, which had occurred across three main volcanic systems: Eldey, Reykjanes-Svartsengi, and Krýsuvík, had significantly decreased. These data indicated that the injection of magma beneath Thorbjorn had stopped, though there were indications of deformation over a larger area. On 4 May the Aviation Color Code was lowered to Green.

Source: Icelandic Meteorological Office (IMO)

25 March-31 March 2020 Cite this Report

There were more than 6,000 earthquakes recorded beneath the Reykjanes peninsula as of 26 March, making this period of unrest the largest seismic crisis ever recorded in this part of the country since digital monitoring started in 1991, according to IMO. The seismicity occurred across three main volcanic systems: Eldey, Reykjanes-Svartsengi, and Krýsuvík. Uplift continued to be detected in the Thorbjorn area totaling about 70-80 mm; the deformation rate was lower than in January and February. Deformation modeling suggested that recent inflation was caused by a second magmatic intrusion at a depth of 3-4 km in an area W of Thorbjorn, close to the intrusion that occurred at the beginning of the year. GPS data suggested a small deformation pattern detectable over a regional area, far beyond the Thorbjorn area.

Source: Icelandic Meteorological Office (IMO)

11 March-17 March 2020 Cite this Report

On 18 March IMO raised the Aviation Color Code for Reykjanes to Yellow noting that recent InSAR and GPS data indicated that during the second week of March deformation had restarted. The uplift was concentrated in the same place as that recorded in January-February, though at a slower rate. The cause of the deformation was likely an intrusion of magma at 4.5 km depth.

A large (M 4.6) earthquake was recorded on 12 March and located 3.5 km NE of Thorbjorn, possibly connected to the inflation. A sequence of aftershocks lasted for a few days and was characterized by eight earthquakes over M 3 and about 80 events with magnitudes between 2 and 3. Since the large event a total of 850 earthquakes were recorded in the area.

Source: Icelandic Meteorological Office (IMO)

19 February-25 February 2020 Cite this Report

On 25 February IMO reported that seismic activity at Reykjanes, in an area N of the town of Grindavík, had significantly decreased during the previous few days, and inflation was not detected in GPS and InSAR data. The Aviation Color Code was lowered to Green. Preliminary data suggested a small deflation signal beginning mid-February, though further analysis was needed for confirmation. The report warned the public not to explore lava tubes in the Eldvörp area as gas measurements showed a dangerous level of oxygen depletion; there are no pre-unrest measurements existing for comparison.

Source: Icelandic Meteorological Office (IMO)

12 February-18 February 2020 Cite this Report

On 15 February IMO reported that seismicity at Reykjanes, in an area N of the town of Grindavík, remained above background levels even though activity had been decreasing since the end of January. Two earthquakes larger than M 3 were detected; one of them, an M 3.1, was recorded at 0826 on 14 February. The rate of deformation had slightly increased. The Aviation Code remained at Yellow.

Source: Icelandic Meteorological Office (IMO)

5 February-11 February 2020 Cite this Report

On 7 February IMO reported that data collected during the previous week indicated that a magma body was located 3-5 km beneath Reykjanes. Earthquake activity had decreased during the previous two days, though inflation was ongoing, reaching 5 cm. The Aviation Code remained at Yellow.

Source: Icelandic Meteorological Office (IMO)

22 January-28 January 2020 Cite this Report

IMO reported possible magma accumulation beneath Reykjanes, centered along the plate boundary below the Svartsengi fissure system, just W of Thorbjorn. Deformation began on 21 January and was unusually rapid, with the rate of inflation occurring at 3-4 mm per day (3 cm total by 29 January), as detected by InSAR and continuous GPS data. Magma accumulation, if that was causing the inflation, was small with an estimate volume of 1 million cubic meters, at 3-5 km depth. Deformation on the Reykjanes peninsula had been measured for three decades with no previously comparable signals.

An earthquake swarm accompanied the deformation, just E of the center of the inflation. The largest earthquakes were M 3.6 and 3.7, recorded on 22 January, and felt widely on the Reykjanes peninsula and all the way to Borgarnes region. Earthquake swarms are relatively common, though coupled with deformation caused IMO to raise the Aviation Code to Yellow on 26 January. The swarm was declining by 26 January. On 29 January IMO stated that data showed continuing uplift and the earthquake swarm was ongoing.

Source: Icelandic Meteorological Office (IMO)

The Global Volcanism Program has no Bulletin Reports available for Reykjanes.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Cones
Feature Name	Feature Type	Elevation	Latitude	Longitude
Bergholl	Shield volcano	37 m	63° 53' 0" N	22° 44' 0" W
Haleyjabunga	Shield volcano	30 m	63° 49' 0" N	22° 39' 0" W
Hrolfsvikurhraun	Shield volcano		63° 50' 0" N	22° 20' 0" W
Lagafell	Shield volcano	91 m	63° 53' 0" N	22° 33' 0" W
Langholl	Shield volcano	73 m	63° 53' 0" N	22° 40' 0" W
Sandfellshaed	Shield volcano	74 m	63° 52' 0" N	22° 35' 0" W
Skalafell	Shield volcano	76 m	63° 49' 0" N	22° 42' 0" W
Thrainsskjöldur	Shield volcano		63° 53' 0" N	22° 12' 0" W
Vatnsheidi	Shield volcano	140 m	63° 51' 0" N	22° 23' 0" W
Craters
Feature Name	Feature Type	Elevation	Latitude	Longitude
Arnarsetur	Crater Row	80 m	63° 53' 0" N	22° 25' 0" W
Badsvallagigir	Crater Row		63° 53' 0" N	22° 25' 0" W
Borgarhraun	Crater Row	121 m	63° 50' 0" N	22° 19' 0" W
Dalahraun	Crater Row		63° 52' 0" N	22° 20' 0" W
Eldeyjarbodi	Submarine crater		63° 26' 0" N	23° 50' 0" W
Eldvorp	Crater Row	60 m	63° 51' 0" N	22° 35' 0" W
Fellshraun	Crater Row		63° 53' 0" N	22° 25' 0" W
Geirfugladrangur	Submarine crater		63° 26' 0" N	23° 17' 0" W
Grjothryggur	Submarine crater
Gullholl	Submarine crater
Haugur	Crater Row		63° 52' 0" N	22° 37' 0" W
Hreidhur	Crater Row		63° 50' 0" N	22° 40' 0" W
Illahraun	Crater Row	40 m	63° 52' 0" N	22° 28' 0" W
Kalfellshraun	Crater Row		63° 56' 0" N	22° 19' 0" W
Klofningahraun	Crater Row		63° 50' 0" N	22° 33' 0" W
Langagrunn	Submarine crater
Melholl	Crater Row	140 m	63° 50' 0" N	22° 25' 0" W
Raudholar	Crater Row	40 m	63° 50' 0" N	22° 40' 0" W
Reykjaneshyggur	Fissure vent	80 m	63° 40' 0" N	22° 20' 0" W
Stampar	Crater Row	30 m	63° 50' 0" N	22° 42' 0" W
Steinaholl	Submarine crater
Stori-Brandur	Submarine crater
Sundhnukar	Crater Row	100 m	63° 53' 0" N	22° 23' 0" W
Svartsengi	Fissure vent
Syrfellshraun	Crater Row		63° 49' 0" N	22° 40' 0" W
Tjaldstadagja	Crater Row	30 m	63° 51' 0" N	22° 39' 0" W

Basic Data Volcano Number Last Known Eruption Elevation Latitude Longitude 371020 1831 CE 140 m / 459 ft 63.817°N 22.717°W Volcano Types Crater rows Shield(s) Fissure vent(s) Rock Types Major Basalt / Picro-Basalt Tectonic Setting Rift zone Oceanic crust (< 15 km) Population Within 5 km Within 10 km Within 30 km Within 100 km 13,995 13,995 15,542 192,922

Geological Summary The Reykjanes volcanic system at the SW tip of the Reykjanes Peninsula, where the Mid-Atlantic Ridge rises above sea level, comprises a broad area of postglacial basaltic crater rows and small shield volcanoes. The submarine Reykjaneshryggur volcanic system is contiguous with and is considered part of the Reykjanes volcanic system, which is the westernmost of a series of four closely-spaced en-echelon fissure systems that extend diagonally across the Reykjanes Peninsula. Most of the subaerial part of the system (also known as the Reykjanes/Svartsengi volcanic system) is covered by Holocene lavas. Subaerial eruptions have occurred in historical time during the 13th century at several locations on the NE-SW-trending fissure system, and numerous submarine eruptions dating back to the 12th century have been observed during historical time, some of which have formed ephemeral islands. Basaltic rocks of probable Holocene age have been recovered during dredging operations, and tephra deposits from earlier Holocene eruptions are preserved on the nearby Reykjanes Peninsula. This volcano is located within the Reykjanes, a UNESCO Global Geopark property. References The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Andrew R E B, Gudmundsson A, 2007. Distribution, structure, and formation of Holocene lava shields in Iceland. J. Volcanol. Geotherm. Res., 168: 137-154. Gudmundsson A T, 1986. Iceland-Fires. Reykjavik: Vaka-Helgafell, 168 p. IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior. Jakobsson S P, Jonasson K, Sigurdsson I A, 2008. The three igneous rock series of Iceland. Jokull, 58: 117-138. Jakobsson S P, Jonsson J, Shido F, 1978. Petrology of the western Reykjanes Peninsula, Iceland. J Petr, 19: 669-705. Jenness M H, Clifton A E, 2009. Controls on the geometry of a Holocene crater row: a field study from southwest Iceland. Bull Volcanol, 71: 715-528. https://doi.org/10.1007/s00445-009-0267-9 Johannesson H, Einarsson S, 1988. The age of Illahraun at Svartsengi. Fjolrit Natturufraedistofnunar, 7: 1-11 (in Icelandic with English summary). Johannesson H, Saemundsson K, 1998. Geological map of Iceland, 1:500,000. Tectonics. Icelandic Inst Nat Hist, Reykjavik. Jonsson J, 1978. Geology of the Reykjanes Peninsula. Orkustofnun Jardhitadeild, OS-JHD-7831, Geol maps and 303 p text (in Icelandic). Saemundsson K, Einarsson S, 1980. Geological map of Iceland, sheet 3, south-west Iceland. Icelandic Museum Nat Hist & Iceland Geodetic Surv, 1:250,000 geol map. Saemundsson K, Sigurgeirsson M A, Fridleifsson G O, 2020. Geology and structure of the Reykjanes volcanic system, Iceland. Journal of Volcanology and Geothermal Research 391 (2020) 106501. https://doi.org/10.1016/j.jvolgeores.2018.11.022 Sigurgeirsson M A, 1992. Tephra fall formations on the Reykjanes Peninsula. Unpublished Master's thesis, Univ Iceland, 114 p. Steinthorsson S, et al., 2002. Catalog of Active Volcanoes of the World - Iceland. Unpublished manuscript. Thordarson T, Hoskuldsson A, 2008. Postglacial eruptions in Iceland. Jokull, 58: 197-228.

Eruptive History

There is data available for 19 confirmed Holocene eruptive periods.

Deformation History

There is no Deformation History data available for Reykjanes.

Emission History

There is no Emissions History data available for Reykjanes.

Photo Gallery

The Reykjanes volcanic system at the SW tip of the Reykjanes Peninsula in Iceland comprises a broad area of postglacial crater rows and small shield volcanoes. Snow-covered Sandfellshæd shield volcano (lower center), capped by a small crater of approximately 400 m diameter, rises less than 100 m above the Atlantic Ocean to the south (background). Most of the volcanic system is covered by Holocene lava flows. Eruptions have occurred in historical time. Eruptions during the 13th century distributed tephra across the Reykjanes peninsula and lava covered about 50 km².

Photo by Helgi Torfason (courtesy of Richie Williams, U S Geological Survey, published in Gudmundsson, 1986). The snow-covered Reykjanes volcanic system forms the SW tip of the Reykjanes Peninsula, where the Mid-Atlantic Ridge rises above sea level. It is the westernmost of a series of four closely spaced, NE-SW-trending, en-echelon fissure systems that extend diagonally across the Reykjanes Peninsula. Most of this system is covered by Holocene lavas, and eruptions occurred during the 13th century at several locations.

Photo by Oddur Sigurdsson, 1998 (Icelandic National Energy Authority). The submarine Reykjaneshryggur volcanic system, lying off the southwest tip of Iceland, is part of the Mid-Atlantic Ridge, which extends onto the Reykjanes Peninsula (foreground). A small plume of steam from geothermal activity is visible (middle left). Numerous submarine eruptions at Reykjaneshryggur dating back to the 13th century have been observed, some of which have formed short-lived islands. Submarine eruptions have been characterized by phreatomagmatic or Surtseyan explosive activity, depositing tephra on land. Subaerial eruptions have been typified by effusive activity, producing lava flows on Reykjanes Peninsula.

Photo by Oddur Sigurdsson, 1998 (Icelandic National Energy Authority).

GVP Map Holdings

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included. The maps database originated over 30 years ago, but was only recently updated and connected to our main database. We welcome users to tell us if they see incorrect information or other problems with the maps; please use the Contact GVP link at the bottom of the page to send us email.

Smithsonian Sample Collections Database

The following 17 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number	Sample Description	Lava Source	Collection Date
NMNH 115614	Tholeiite	ARNARSETUR	--
NMNH 115616	Tholeiite	--	--
NMNH 115618	Tholeiite	TJALDSTADAGJA	--
NMNH 115619	Tholeiite	SYRFELLSHRAUN	--
NMNH 115621	Tholeiite	STAMPAR	--
NMNH 115622	Olivine Tholeiite	LANGHOLL	--
NMNH 115625	Picrite Basalt	--	--
NMNH 115626	Picrite Basalt	--	--
NMNH 115627	Olivine Tholeiite	THRAINSSKJOLDUR	--
NMNH 115628	Olivine Tholeiite	THRAINSSKJOLDUR	--
NMNH 115629	Olivine Tholeiite	LANGHOLL	--
NMNH 115630	Olivine Tholeiite	LANGHOLL	--
NMNH 115631	Olivine Tholeiite	THRAINSSKJOLDUR	--
NMNH 115632	Olivine Tholeiite	THRAINSSKJOLDUR	--
NMNH 115633	Tholeiite	--	--
NMNH 115634	Picrite Basalt	VATNSHEIDI	--
NMNH 115636	Picrite Basalt	HROLFSVIKURHRAUN	--

External Sites

Catalogue of Icelandic Volcanoes (Link to Reykjanes)	The Catalogue of Icelandic Volcanoes is an interactive, web-based tool, containing information on volcanic systems that belong to the active volcanic zones of Iceland. It is a collaboration of the Icelandic Meteorological Office (the state volcano observatory), the Institute of Earth Sciences at the University of Iceland, and the Civil Protection Department of the National Commissioner of the Iceland Police, with contributions from a large number of specialists in Iceland and elsewhere. This official publication is intended to serve as an accurate and up-to-date source of information about active volcanoes in Iceland and their characteristics. The Catalogue forms a part of an integrated volcanic risk assessment project in Iceland GOSVÁ (commenced in 2012), as well as being part of the effort of FUTUREVOLC (2012-2016) on establishing an Icelandic volcano supersite.
Copernicus Browser	The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions.
MIROVA	Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.
MODVOLC Thermal Alerts	Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.
WOVOdat    Single Volcano View    Temporal Evolution of Unrest    Side by Side Volcanoes	WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore. GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments.
Volcanic Hazard Maps	The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter.
IRIS seismic stations/networks	Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Reykjanes. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice.
UNAVCO GPS/GNSS stations	Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Reykjanes. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player.
DECADE Data	The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO2 to the atmosphere, but installing CO2 monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere.
Large Eruptions of Reykjanes	Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
EarthChem	EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).