Torfajokull

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 63.92°N
  • 19.17°W

  • 1259 m
    4130 ft

  • 372050
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Torfajokull.

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

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

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude
372050

1477 CE

1259 m / 4130 ft

63.92°N
19.17°W

Volcano Types

Stratovolcano
Caldera
Fissure vent(s)
Lava dome(s)

Rock Types

Major
Rhyolite
Basalt / Picro-Basalt
Andesite / Basaltic Andesite
Dacite
Minor
Trachyandesite / Basaltic trachy-andesite

Tectonic Setting

Rift zone
Oceanic crust (< 15 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
0
0
7
16,304

Geological Summary

The Torfajökull central volcano, located north of Myrdalsjökull and south of Thorisvatn lake, is cut by a 12-km-wide caldera that formed during the Pleistocene. Torjajökull consists of the largest area of silicic and intermediate volcanism in Iceland; about 225 cu km of silicic extrusive rocks are exposed. The dominantly rhyolitic complex rises about 500 m above surrounding basaltic plains and is elongated in a WNW-ESE direction. Most rhyolitic lava flows were erupted subglacially, forming silicic hyaloclastites that form ridge and dome-shaped breccias. During postglacial times only a narrow fissure zone at the western end has been active, producing mostly silicic lava flows, lava domes, and tephras. The most recent silicic eruption produced the Hrafntinnuhraun lava flow about 900 CE. The fissure system is along trend with and was active at the same time as the basaltic Veidivötn fissure system of Bárdarbunga central volcano in 1477 CE. The small Torfajökull icecap lies mostly outside the SE rim of the caldera, which is the site of vigorous thermal activity over a broad area of 130-140 sq km.

References

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

Gudmundsson A T, 1986b. Iceland-Fires. Reykjavik: Vaka-Helgafell, 168 p.

Gunnarsson B, Marsh B D, Taylor H P Jr, 1998. Generation of Icelandic rhyolites: silicic lavas from the Torfajokull central volcano. J Volc Geotherm Res, 83: 1-45.

Jakobsson S P, 1979. Petrology of recent basalts of the eastern volcanic zone, Iceland. Acta Nat Islandica, 26: 1-103.

Johannesson H, Jakobsson S P, Saemundsson K, 1982. Geological map of Iceland, sheet 6, south Iceland. Icelandic Museum Nat Hist & Iceland Geodetic Surv, 1:250,000 geol map, 2nd edition.

Johannesson H, Saemundsson K, 1998. Geological map of Iceland, 1:500,000. Tectonics. Icelandic Inst Nat Hist, Reykjavik.

Larsen G, 1984. Recent volcanic history of the Veidivotn fissure swarm, southern Iceland - an approach to volcanic risk assessment. J Volc Geotherm Res, 22: 33-58.

MacDonald R, McGarvie D W, Pinkerton H, Smith R L, Palacz Z A, 1990. Petrogenetic evolution of the Torfajokull Volcanic Complex, Iceland I. Relationship between the magma types. J Petr, 31: 429-459.

McGarvie D M, MacDonald R, Pinkerton H, Smith R L, 1990. Petrogenetic evolution of the Torfajokull Volcanic Complex, Iceland II. The role of magma mixing. J Petr, 31: 461-481.

McGarvie D W, Burgess R, Tindle A G, Tuffen H, Stevenson J A, 2006. Pleistocene rhyolitic volcanism at Torfajokull, Iceland: eruption ages, glaciovolcanism, and geochemical evolution. Jokull, 56: 57-75.

Saemundsson K, 1972. Notes on the geology of the Torfajokull central volcano. Natturufraedingurinn, 42: 81-89 (in Icelandic with English summary).

Saemundsson K, 1988. The geology of the Torfajokull region. Arbok Ferdafelags Islands 1988, p 164-180.

Soosalu H, Einarsson P, 2004. Seismic constraints on magma chambers at Hekla and Torfajokull volcanoes, Iceland. Bull Volc, 66: 276-286.

Soosalu H, Einarsson P, 1997. Seismicity around the Hekla and Torfajokull volcanoes, Iceland, during a volcanically quiet period, 1991-1995. Bull Volc, 59: 36-48.

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.

Tuffen H, Gilbert J, McGarvie D, 2001. Products of an effusive subglacial rhyolite eruption: Blahnukur, Torfajokull, Iceland. Bull Volc, 63: 179-190.

Wilson L, Fagents S A, Robshaw L E, Scott E D, 2007. Vent geometry and eruptions conditions of the mixed rhyolite-basalt Namshraun lava flow, Iceland. J Volc Geotherm Res, 164: 127-141.

Eruptive History


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


Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1477 Mar Unknown Confirmed 2 Historical Observations N of caldera (Namshraun, Laugahraun)
1170 (?) Unknown Confirmed   Tephrochronology W side of caldera (Hrafntinnuhraun)
0870 (?) Unknown Confirmed 3 Tephrochronology W side of caldera (Hrafntinnuhraun)
0150 ± 100 years Unknown Confirmed 3 Tephrochronology N of caldera (Domadalshraun)
1150 BCE ± 100 years Unknown Confirmed   Tephrochronology N of caldera (Domadalshraun)
1550 BCE ± 500 years Unknown Confirmed   Tephrochronology W side of caldera (Markafljot domes)
4550 BCE ± 500 years Unknown Confirmed   Tephrochronology N of caldera (Haolduhraun)
4850 BCE (?) Unknown Confirmed   Tephrochronology W of caldera (Laufafell domes)
5050 BCE (?) Unknown Confirmed   Tephrochronology Hrafntinnusker and Domadalshraun
6050 BCE (?) Unknown Confirmed   Tephrochronology W side of caldera (Slettahraun)

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
Bláhnúkur Tuya
Gvendarhyran Tuya
Illihnúkur Tuya
Kirkjufell Tuya
Raudfossafjöll Tuya

Craters

Feature Name Feature Type Elevation Latitude Longitude
Domadalshraun Fissure vent 680 m 64° 2' 0" N 19° 7' 0" W
Grakolluhraun Fissure vent 64° 2' 0" N 19° 3' 0" W
Haolduhraun Fissure vent 64° 0' 0" N 19° 10' 0" W
Hraftinnuhraun Crater Row 944 m 63° 57' 0" N 19° 16' 0" W
Laufahraun Fissure vent 63° 55' 0" N 19° 25' 0" W
Laugahraun Crater Row 63° 59' 0" N 19° 5' 0" W
Merkurhraun Fissure vent 64° 8' 0" N 19° 33' 0" W
Namshraun Crater Row 64° 1' 0" N 19° 2' 0" W
Slettahraun Fissure vent 63° 57' 0" N 19° 13' 0" W

Domes

Feature Name Feature Type Elevation Latitude Longitude
Hraftinnusker Dome 1140 m 63° 56' 0" N 19° 11' 0" W
Laufafell Dome 63° 56' 0" N 19° 21' 0" W
Markarfljot Dome 63° 57' 0" N 19° 20' 0" W

Photo Gallery


The viscous Laugahraun lava flow was emplaced in 1477 just inside the northern rim of Torfajökull caldera. Minor amounts of silicic tephra and lava were erupted from Torfajökull at the southern end of the Veidivotn fissure, which produced a major basaltic explosive eruption in March 1477. Three silicic lava flows--north and south Namshraun and Laugahraun--were emplaced near the northern margin of the Torfajökull caldera.

Photo by Richie Williams, 1981 (U.S. Geological Survey).
The silicic Hrafntinnuhraun lava flow and tephra were erupted about 870 AD at the SW end of a fissure system that also produced basaltic eruptions from the Vatnaoldur fissure of Bardarbunga volcano at this same time. The Hrafntinnuhraun crater row was the source of the roughly 870 AD "Settlement Layer" tephra that forms a prominent time marker throughout SW Iceland.

Photo by Richie Williams, 1981 (U.S. Geological Survey).
The Torfajökull central volcano is cut by a 12-km-wide caldera that formed during the Pleistocene. Torfajökull is of one of the largest areas of silicic and intermediate volcanism in Iceland. The Laugahraun (lower left) and Domadalshraun (right center) lava flows, seen here from the SE, are located just within and north of, respectively, the northern caldera rim. During postglacial times only a narrow fissure zone at the western end of Torfajökull has been active, producing mostly silicic lava flows, lava domes, and tephras.

Photo by Oddur Sigurdsson, 1977 (Icelandic National Energy Authority).

Smithsonian Sample Collections Database


A listing of samples from the Smithsonian collections will be available soon.

Affiliated Sites

Large Eruptions of Torfajokull 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).
MODVOLC - HIGP MODIS Thermal Alert System 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.
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.