Most Recent Weekly Report: 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 Met Office (IMO)

Weekly Reports - Index

2020: January | February | March

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 Met 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 Met 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 Met 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 Met 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 Met 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 Met 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 63.85°N 22.566°W Volcano Types Crater rows Shield(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. 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 22 Holocene eruptive periods.

Start Date	Stop Date	Eruption Certainty	VEI	Evidence	Activity Area or Unit
[ 1970 Jul 2 (?) ± 182 days ]	[ Unknown ]	Uncertain	0		Reykjaneshryggur (Eldeyjarbodi)
[ 1966 Jul 2 ± 182 days ]	[ Unknown ]	Uncertain	0		Reykjaneshryggur (Eldeyjarbodi)
1830 Mar 13 (?)	1831 Mar (?)	Confirmed	3	Historical Observations	Reykjaneshryggur (Eldeyjarbodi)
1783 May 1 (in or before)	1783 Aug 15 ± 60 days	Confirmed	3	Historical Observations	Reykjaneshryggur (Nyey)
[ 1661 Dec ]	[ Unknown ]	Discredited
1583 Jul 15 ± 45 days	Unknown	Confirmed	2	Historical Observations	Reykjaneshryggur (near Eldeyjar Islands)
1240	Unknown	Confirmed	1	Historical Observations	Reykjaneshryggur, Arnarsetur, Illahraun
1238	Unknown	Confirmed	0	Historical Observations	Reykjaneshryggur
1231	Unknown	Confirmed	3	Historical Observations	Reykjaneshryggur, R-10 tephra
1226 Jul 15 ± 45 days	1227 (?)	Confirmed	4	Historical Observations	Reykjaneshryggur, R-9 tephra
1223	Unknown	Confirmed	3	Historical Observations	Reykjaneshryggur, R-8 tephra
1211	Unknown	Confirmed		Historical Observations	Stampar, Karlsgigur
1210	Unknown	Confirmed	3	Historical Observations	Vatnsfellsgigur
1179 (in or before)	Unknown	Confirmed	2	Historical Observations	Reykjaneshryggur, R-5 and R-6 tephras
0920 (?)	Unknown	Confirmed		Tephrochronology	Reykjaneshryggur (near Eldey), R-4 tephra
0200 BCE (?)	Unknown	Confirmed	0	Radiocarbon (uncorrected)	Lambagjá
0400 BCE ± 100 years	Unknown	Confirmed	2	Radiocarbon (uncorrected)	Sundhnukar
1800 BCE ± 300 years	Unknown	Confirmed	2	Tephrochronology	Reykjaneshryggur, Stampar, R-2, R-3 tephras
3800 BCE ± 300 years	Unknown	Confirmed		Tephrochronology	Reykjaneshryggur, R-1 tephra
4000 BCE (?)	Unknown	Confirmed	0	Tephrochronology	Sandfellshaed
5040 BCE ± 100 years	Unknown	Confirmed	0	Radiocarbon (uncorrected)	Hopsnes
8000 BCE (?)	Unknown	Confirmed	0	Tephrochronology	Thrainskjöldur

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, where the Mid-Atlantic Ridge rises above sea level, comprises a broad area of postglacial crater rows and small shield volcanoes. Snow-covered Sandfellshæd shield volcano (lower center), capped by a small crater, rises only 74 m above the Atlantic Ocean to the south. Most of the volcanic system is covered by Holocene lava flows. Eruptions have occurred in historical time during the 13th century at several locations on the NE-SW-trending fissure system. Photo by Helgi Torfason (courtesy of Richie Williams, U S Geological Survey, published in Gudmundsson, 1986).
The two westernmost of five NE-SW-trending volcanic systems on the Reykjanes Peninsula cut diagonally across this aerial photo. The Reykjanes volcanic system, which lies near the SW tip of the peninsula, where the Mid Atlantic Ridge rises above sea level, has produced Holocene lava fields that extend to the western and southern coasts. The Krísuvík volcanic system, on the right side of the photo, has produced several eruptions since the settlement of Iceland. The latest of these took place during the 14th century. Photo courtesy of Richie Williams (U.S. Geological Survey).
The snow-mantled Reykjanes volcanic system forms the SW tip of the Reykjanes Peninsula, where the Mid-Atlantic Ridge rises above sea level. The Reykjanes volcanic system 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 the Reykjanes volcanic system is covered by Holocene lavas, and eruptions have occurred in historical time during the 13th century at several locations. Photo by Oddur Sigurdsson, 1998 (Icelandic National Energy Authority).
The submarine Reykjaneshryggur volcanic system, lying off the SW tip of Iceland at the top of the photo, is part of the Mid-Atlantic Ridge, which extends onto the Reykjanes Peninsula in the foreground. Numerous submarine eruptions at Reykjaneshryggur dating back to the 12th century have been observed during historical time, some of which have formed ephemeral islands. Tephra deposits from earlier Holocene eruptions are preserved on the Reykjanes Peninsula in the foreground. 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.

Title: Geomorphology of Iceland Publisher: University of Goteborg, Dept Phys Geog Country: Iceland Year: 1984 Map Type: Geology (Geomorphology) Scale: 1:1,750
Title: Geographical Names of Iceland Publisher: University of Goteborg, Dept Phys Geog Country: Iceland Year: 1984 Map Type: Unknown Scale: 1:1,750

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.
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.
Sentinel Hub Playground Sentinel Hub EO Browser	The Sentinel Hub Playground provides a quick look at any Sentinel-2 image in any combination of the bands and enhanced with image effects; Landsat 8, DEM and MODIS are also available. Sentinel Hub is an engine for processing of petabytes of satellite data. It is opening the doors for machine learning and helping hundreds of application developers worldwide. It makes Sentinel, Landsat, and other Earth observation imagery easily accessible for browsing, visualization and analysis. Sentinel Hub is operated by Sinergise
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.
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.
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).