Hengill

Photo of this volcano
Google Earth icon
  Google Earth Placemark
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 64.08°N
  • 21.32°W

  • 803 m
    2634 ft

  • 371050
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Hengill.

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

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

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 1900 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.

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
0150 ± 75 years Unknown Confirmed 2 Radiocarbon (corrected) Nesjahraun, Reykjafellshraun
0080 BCE ± 75 years Unknown Confirmed 2 Radiocarbon (uncorrected) Eldborg undir Meitlum
1730 BCE ± 50 years Unknown Confirmed 0 Radiocarbon (corrected) Thjófahraun
3250 BCE (?) Unknown Confirmed 0 Radiocarbon (corrected) Leitahraun, Ellidaárhraun
3750 BCE (?) Unknown Confirmed 2 Radiocarbon (corrected) Hagavikurhraun
5000 BCE (?) Unknown Confirmed   Tephrochronology Eldborgir
5550 BCE ± 500 years Unknown Confirmed 0 Tephrochronology Stangarhals
7100 BCE (?) Unknown Confirmed 0 Tephrochronology Gjabakkahraun
7300 BCE (?) Unknown Confirmed   Tephrochronology Brunnar/Skogarkot
7550 BCE (?) Unknown Confirmed 0 Tephrochronology Selvogsheidi
8200 BCE (?) Unknown Confirmed 0 Tephrochronology Hafnarhraun
8250 BCE (?) Unknown Confirmed 0 Radiocarbon (corrected) Thingvallahraun
8350 BCE (?) Unknown Confirmed 0 Radiocarbon (corrected) SSW of Hengill (Hellisheid-A)

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" N 21° 24' 0" W
Burfell I Olfusi
    Blaufdel
Shield volcano 200 m 63° 55' 0" N 21° 28' 0" W
Dimmadalshaedh Shield volcano 200 m 63° 55' 0" N 21° 25' 0" W
Gjabakkahraun Shield volcano 64° 15' 0" N 20° 56' 0" W
Hildarhraun Shield volcano 63° 52' 0" N 21° 39' 0" W
Sandey Tuff cone 174 m 64° 11' 0" N 21° 10' 0" W
Selvogsheidi Shield volcano 192 m 63° 53' 0" N 21° 35' 0" W

Craters

Feature Name Feature Type Elevation Latitude Longitude
Eldborg undir Meitlum Crater Row 320 m 63° 59' 0" N 21° 25' 0" W
Eldborgir Crater Row 540 m 64° 15' 0" N 20° 55' 0" W
Eldborgir-Tindaskaga Crater Row 500 m 64° 14' 0" N 20° 52' 0" W
Eldborg-Thingvallavatn Crater Row 120 m 64° 9' 0" N 21° 12' 0" W
Gramelur Crater Row 140 m 64° 8' 0" N 21° 10' 0" W
Hagavikurhraun Fissure vent 64° 5' 0" N 21° 13' 0" W
Hveradalahraun Crater Row 64° 1' 0" N 21° 24' 0" W
Litlahraun Crater Row 63° 53' 0" N 21° 30' 0" W
Nesjahraun Fissure vent 140 m 64° 9' 0" N 21° 12' 0" W
Reykjafellsgigir Crater Row 64° 2' 0" N 21° 22' 0" W
Sandfellsgigir Crater Row 295 m 63° 58' 0" N 21° 28' 0" W
Skardsmyrarhraun Crater Row 390 m 64° 2' 0" N 21° 20' 0" W
Stangarhals Fissure vent 230 m 64° 7' 0" N 21° 14' 0" W
Thjofahraun Fissure vent 660 m 64° 20' 0" N 20° 49' 0" W
Tjarnahnukur Crater Row 520 m 64° 5' 0" N 21° 13' 0" W

Thermal

Feature Name Feature Type Elevation Latitude Longitude
Hellisheidi Thermal
Nesjavellir Thermal
Thingvellir, the renowned site of Althing, the old Icelandic outdoor legislative assembly, lies immediately north of Thingvallavatn lake. Old trails from every corner of Iceland led to Thingvellir ("Parliament Plains"), where the country's first parliamentary assembly was held in 930 AD. This view was taken looking NE from atop the Almannagjá, the fault-bounded margin of the Hengill graben, where the Lögberg, the proclaiming of the laws of the land, took place. The flat-lying, faulted lava flows of the Hengill volcanic system form the middle distance.

Photo by Bill Rose, 1980 (Michigan Technological University).
An aerial view from the NE shows the Hengill central volcano on the center horizon rising above Thingvallavatn lake. Steam rises from the Nesjavellir geothermal area in front of Hengill. NE-trending fault scarps extend into the lake, and the island in the foreground is part of a Pleistocene subglacial ridge. Holocene fissure-fed eruptions have occurred from vents both NE and SW of the Hengill central volcano.

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 NE. Graben structures in the foreground cut the Thingvallahraun lava flow in the foreground, which was erupted about 10,200 years ago.

Photo by Lee Siebert, 2008 (Smithsonian Institution).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

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. J Volc Geotherm Res, 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. J Volc Geotherm Res, 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. J Volc Geotherm Res, 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, 1977a. 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. Geochem Geophys Geosyst, 6(12): 10.1029/2005CG001021.

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

Volcano Types

Crater rows
Shield(s)

Tectonic Setting

Rift zone
Oceanic crust (< 15 km)

Rock Types

Major
Basalt / Picro-Basalt
Andesite / Basaltic Andesite
Rhyolite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
5,722
5,722
124,106
204,855

Affiliated Databases

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).
WOVOdat 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.
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).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.