Global Volcanism Program

Hengill

Google Earth Placemark with Features

Cite Volcano Profile

Catalogue of Icelandic Volcanoes (Link to Hengill)

Iceland
Iceland Neovolcanic Rift Volcanic Province
Cluster | Crater rows
150 CE

Country
Volcanic Region
Landform | Volc Type
Last Known Eruption

64.083°N
21.416°W
803 m
2,635 ft
371050

Latitude
Longitude
Summit
Elevation
Volcano
Number

The Global Volcanism Program has no activity reports available for Hengill.

The Global Volcanism Program has no Weekly Reports available for Hengill.

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

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude

371050

150 CE

803 m / 2,635 ft

64.083°N
21.416°W

Morphology

Volcano Landform
Cluster

Volcano Types
Crater rows
Shield(s)

Rock Types

Major
Basalt / Picro-Basalt
Andesite / Basaltic Andesite
Rhyolite

Tectonic Setting

Rift zone
Oceanic crust (< 15 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km

5,722
5,722
124,106
204,855

Geological Summary

The Hengill volcanic system, cutting through Thingvallavatn lake, consists of a series of NE-SW-trending fissure vents, crater rows, and small shield volcanoes occupying a strongly faulted graben. Hengill is the easternmost of a series of four closely spaced basaltic fissure systems that cut diagonally across the Reykjanes Peninsula and lies at the triple junction of the Reykjanes Peninsula volcanic zone, the Western volcanic zone, and the South Iceland seismic zone. Postglacial lava flows surface much of the volcanic system. The latest eruption was radiocarbon dated about 1,900 years before present. An eruption in the Hellisheidi area once thought to have occurred around 1000 CE at the time of a meeting of the Icelandic parliament at Thingvellir is now known to have occurred at a vent about 5 km away in the Brennisteinsfjöll volcanic system. The high-temperature Nesjavellir geothermal area NE of the uplifted hyaloclastite ridge forming the Hengill central volcano and the Helllisheidi geothermal field SW of Hengill are major producers of geothermal energy for Reykjavik.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Botz R, Winckler G, Bayer R, Schmitt M, Schmidt M, Garbe-Schonberg D, Stoffers P, Kristjansson J K, 1999. Origin of trace gases in submarine hydrothermal vents of the Kolbeinsey Ridge, north Iceland. Earth Planet Sci Lett, 171: 83-93.

Clifton A E, Sigmundsson F, Feigl K L, Gudmundsson G, Arnadottir T, 2002. Surface effects of faulting and deformation resulting from magma accumulation at the Hengill triple junction, SW Iceland, 1994-1998. Journal of Volcanology and Geothermal Research, 115: 233-255.

Eason D E, Sinton J M, 2009. Lava shields and fissure eruptions of the Western Volcanic Zone, Iceland: evidence for magma chambers and crustal interaction. Journal of Volcanology and Geothermal Research, 186: 331-348.

Einarsson T, 1960. The geology of Hellisheidi. Natturufraedingurinn, 30: 151-175 (in Icelandic).

Foulger G R, 1995. The Hengill geothermal area, Iceland: variation of temperature gradients deduced from the maximum depth of seismogenesis. Journal of Volcanology and Geothermal Research, 65: 119-133.

Ivarsson G, 1998. Fumarole gas geochemistry in estimating subsurface temperatures at Hengill in southwestern Iceland. In: Arehart G B, Hulston J R (eds), Water-Rock Interaction, Rotterdam: Balkema, p 459-462.

Jakobsson S P, Jonsson J, Shido F, 1978. Petrology of the western Reykjanes Peninsula, Iceland. J Petr, 19: 669-705.

Jonsson J, 1977. Reykjafellsgigir and Skardsmnyrihraun on Hellisheidi. Natturufraedingurinn, 47: 17-26 (in Icelandic).

Jonsson J, 1978. Geology of the Reykjanes Peninsula. Orkustofnun Jardhitadeild, OS-JHD-7831, Geol maps and 303 p text (in Icelandic).

Jonsson J, 1983. Volcanic eruptions in historical time on the Reykjanes Peninsula, southwest Iceland. Natturufraedingurinn, 52: 127-139 (in Icelandic with English summary).

Saemundsson K, 1965. On the geologic history of Thingvallavatn. Natturufraedingurinn, 35: 103-144 (in Icelandic with German summary).

Saemundsson K, 1967. Vulkanismus und Tektonik des Hengill-Gebietes in Sudwest-Island. Acta Nat Islandica, 2: 1-105.

Saemundsson K, 1982. Excursion guide and road log for field trips A and B. IAVCEI/IAGC 1982 Sci Assembly, Reykjavik, Generation of Major Basalt Types.

Saemundsson K, 1992. Geology of the Thingvallavatn area. Oikos, 64: 40-68.

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.

Sinton J, Gronvold K, Saemundsson K, 2005. Postglacial eruptive history of the Western Volcanic Zone, Iceland. Geochemistry Geophysics Geosystems, 6: Q12009. https://doi.org/10.1029/2005CG001021

Steinthorsson S, et al., 2002. Catalog of Active Volcanoes of the World - Iceland. Unpublished manuscript.

Eruptive History

There is data available for 13 confirmed Holocene eruptive periods.

0150 ± 75 years Confirmed Eruption (Explosive / Effusive) VEI: 2

Episode 1 | Eruption (Explosive / Effusive)

Nesjahraun, Reykjafellshraun

0150 ± 75 years - Unknown

Evidence from Isotopic: 14C (calibrated)

List of 5 Events for Episode 1 at Nesjahraun, Reykjafellshraun

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Phreatic activity
- - - -	- - - -	Lava flow
- - - -	- - - -	Cinder Cone
0150 ± 75 years	- - - -	VEI (Explosivity Index)

0080 BCE ± 75 years Confirmed Eruption (Explosive / Effusive) VEI: 2

Episode 1 | Eruption (Explosive / Effusive)

Eldborg undir Meitlum

0080 BCE ± 75 years - Unknown

Evidence from Isotopic: 14C (uncalibrated)

List of 4 Events for Episode 1 at Eldborg undir Meitlum

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Lava flow
- - - -	- - - -	Cinder Cone
0080 BCE ± 75 years	- - - -	VEI (Explosivity Index)

1730 BCE ± 50 years Confirmed Eruption (Explosive / Effusive) VEI: 0

Episode 1 | Eruption (Explosive / Effusive)

Thjófahraun

1730 BCE ± 50 years - Unknown

Evidence from Isotopic: 14C (calibrated)

List of 2 Events for Episode 1 at Thjófahraun

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Lava flow
	1730 BCE ± 50 years	- - - -	VEI (Explosivity Index)

3250 BCE (?) Confirmed Eruption (Explosive / Effusive) VEI: 0

Episode 1 | Eruption (Explosive / Effusive)

Leitahraun, Ellidaárhraun

3250 BCE (?) - Unknown

Evidence from Isotopic: 14C (calibrated)

List of 4 Events for Episode 1 at Leitahraun, Ellidaárhraun

Start Date	End Date	Event Type
- - - -	- - - -	Lava fountains
- - - -	- - - -	Lava flow
- - - -	- - - -	Lava lake
3250 BCE (?)	- - - -	VEI (Explosivity Index)

3750 BCE (?) Confirmed Eruption (Explosive / Effusive) VEI: 2

Episode 1 | Eruption (Explosive / Effusive)

Hagavikurhraun

3750 BCE (?) - Unknown

Evidence from Isotopic: 14C (calibrated)

List of 5 Events for Episode 1 at Hagavikurhraun

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Lava flow
- - - -	- - - -	Ash
- - - -	- - - -	Scoria
3750 BCE (?)	- - - -	VEI (Explosivity Index)

5000 BCE (?) Confirmed Eruption (Explosive / Effusive)

Episode 1 | Eruption (Explosive / Effusive)

Eldborgir

5000 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 1 Events for Episode 1 at Eldborgir

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Lava flow

5550 BCE ± 500 years Confirmed Eruption (Explosive / Effusive) VEI: 0

Episode 1 | Eruption (Explosive / Effusive)

Stangarhals

5550 BCE ± 500 years - Unknown

Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1 at Stangarhals

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Lava flow
	5550 BCE ± 500 years	- - - -	VEI (Explosivity Index)

7100 BCE (?) Confirmed Eruption (Explosive / Effusive) VEI: 0

Episode 1 | Eruption (Explosive / Effusive)

Gjabakkahraun

7100 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 4 Events for Episode 1 at Gjabakkahraun

Start Date	End Date	Event Type
- - - -	- - - -	Lava fountains
- - - -	- - - -	Lava flow
- - - -	- - - -	Lava lake
7100 BCE (?)	- - - -	VEI (Explosivity Index)

7300 BCE (?) Confirmed Eruption (Explosive / Effusive)

Episode 1 | Eruption (Explosive / Effusive)

Brunnar/Skogarkot

7300 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 1 Events for Episode 1 at Brunnar/Skogarkot

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Lava flow

7550 BCE (?) Confirmed Eruption (Explosive / Effusive) VEI: 0

Episode 1 | Eruption (Explosive / Effusive)

Selvogsheidi

7550 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1 at Selvogsheidi

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Lava flow
	7550 BCE (?)	- - - -	VEI (Explosivity Index)

8200 BCE (?) Confirmed Eruption (Explosive / Effusive) VEI: 0

Episode 1 | Eruption (Explosive / Effusive)

Hafnarhraun

8200 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 5 Events for Episode 1 at Hafnarhraun

Start Date	End Date	Event Type	Event Remarks
- - - -	- - - -	Lava fountains
- - - -	- - - -	Lava flow
- - - -	- - - -	Lava flow	Entered water.
- - - -	- - - -	Lava lake
8200 BCE (?)	- - - -	VEI (Explosivity Index)

8250 BCE (?) Confirmed Eruption (Explosive / Effusive) VEI: 0

Episode 1 | Eruption (Explosive / Effusive)

Thingvallahraun

8250 BCE (?) - Unknown

Evidence from Isotopic: 14C (calibrated)

List of 4 Events for Episode 1 at Thingvallahraun

Start Date	End Date	Event Type
- - - -	- - - -	Lava fountains
- - - -	- - - -	Lava flow
- - - -	- - - -	Lava lake
8250 BCE (?)	- - - -	VEI (Explosivity Index)

8350 BCE (?) Confirmed Eruption (Explosive / Effusive) VEI: 0

Episode 1 | Eruption (Explosive / Effusive)

SSW of Hengill (Hellisheid-A)

8350 BCE (?) - Unknown

Evidence from Isotopic: 14C (calibrated)

List of 4 Events for Episode 1 at SSW of Hengill (Hellisheid-A)

Start Date	End Date	Event Type
- - - -	- - - -	Lava fountains
- - - -	- - - -	Lava flow
- - - -	- - - -	Lava lake
8350 BCE (?)	- - - -	VEI (Explosivity Index)

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

Asar

Shield volcano

60 m

63° 55' 0.00" N

21° 24' 0.00" W

Burfell I Olfusi
Blaufdel

Shield volcano

200 m

63° 55' 0.00" N

21° 28' 0.00" W

Dimmadalshaedh

Shield volcano

200 m

63° 55' 0.00" N

21° 25' 0.00" W

Sandey

Tuff cone

174 m

64° 11' 0.00" N

21° 10' 0.00" W

Selvogsheidi

Shield volcano

192 m

63° 53' 0.00" N

21° 35' 0.00" W

Craters

Feature Name

Feature Type

Elevation

Latitude

Longitude

Eldborg undir Meitlum

Crater Row

320 m

63° 59' 0.00" N

21° 25' 0.00" W

Eldborg-Thingvallavatn

Crater Row

120 m

64° 9' 0.00" N

21° 12' 0.00" W

Gramelur

Crater Row

140 m

64° 8' 0.00" N

21° 10' 0.00" W

Hagavikurhraun

Fissure vent

64° 5' 0.00" N

21° 13' 0.00" W

Hveradalahraun

Crater Row

64° 1' 0.00" N

21° 24' 0.00" W

Litlahraun

Crater Row

63° 53' 0.00" N

21° 30' 0.00" W

Nesjahraun

Fissure vent

140 m

64° 9' 0.00" N

21° 12' 0.00" W

Reykjafellsgigir

Crater Row

64° 2' 0.00" N

21° 22' 0.00" W

Sandfellsgigir

Crater Row

295 m

63° 58' 0.00" N

21° 28' 0.00" W

Skardsmyrarhraun

Crater Row

390 m

64° 2' 0.00" N

21° 20' 0.00" W

Stangarhals

Fissure vent

230 m

64° 7' 0.00" N

21° 14' 0.00" W

Tjarnahnukur

Crater Row

520 m

64° 5' 0.00" N

21° 13' 0.00" W

Thermal

Feature Name

Feature Type

Elevation

Latitude

Longitude

Hellisheidi

Thermal

Nesjavellir

Thermal

Photo Gallery

An aerial perspective of Thingvellir, the site of Iceland's historical outdoor parliament, shows the NE-SW-trending Almannagjá fissure cutting diagonally across the left side of the photo. Other prominent fissures cutting lavas of the Hengill volcanic system appear at the right. The Logberg, or law-hill (located at the lower left below the 30-40 m high Almannagja fissure) was the site where the laws of the country were proclaimed during the annual two-week-long parliamentary session in late June and early July.

Copyrighted photo by Katia and Maurice Krafft.

The Hengill volcanic system, mostly located SW of Thingvallavatn lake, consists of a series of NE-SW-trending fissure vents, crater rows, and small shield volcanoes occupying a strongly faulted graben. This view looks NE from the margin of a graben containing Hengill lava at Thingvellir, the site of Iceland's old parliament. The latest eruption of the Hengill volcanic system was radiocarbon dated at about 1900 years before present. Geothermally heated greenhouses, hot springs, and geysers are found at Hveragerdi.

Copyrighted photo by Katia and Maurice Krafft.

An aerial view from the NE shows the Hengill central shield volcano on the center horizon rising above Thingvallavatn lake. Steam rises from the Nesjavallavirkjun geothermal area in front of the peak. NE-trending fault scarps extend into the lake. Holocene fissure-fed eruptions have occurred from vents both northeast and southwest of the Hengill central volcano, with fissures extending into the lake. Just out of the bottom of the picture (north) is an island where phreatomagmatic activity created a tephra ring called Sandey about 1,900 years ago.

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

The Hengill central volcano in the right background rises above Thingvallavatn lake as seen from Thingvellir, the historical site of the Icelandic parliament. Steam clouds rise from the Nesjavellir geothermal area in this view from the northeast. Graben structures in the foreground cut the Thingvallahraun lava flow in the foreground, which was erupted about 10,000 years ago. The cone in the lake on the left is Sandey, a tuff ring formed in a phreatomagmatic eruption about 1,900 years ago.

Photo by Lee Siebert, 2008 (Smithsonian Institution).

Smithsonian Sample Collections Database

There are no samples for Hengill in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

External Sites

Catalogue of Icelandic Volcanoes (Link to Hengill)

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 Hengill. 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 Hengill. 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 Hengill

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).