Global Volcanism Program

The Global Volcanism Program has no activity reports for Torfajökull.

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

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

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

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude

372050

1477 CE

1280 m / 4198 ft

63.892°N
19.122°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 Trachyandesite

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 km3 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 km2.

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, 1986. 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

There is data available for 10 Holocene eruptive periods.

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)

Deformation History

There is data available for 3 deformation periods. Expand each entry for additional details.

Deformation during 2003 - 2007 [Subsidence; Observed by InSAR]

Start Date: 2003

Stop Date: 2007

Direction: Subsidence

Method: InSAR

Magnitude: Unknown

Spatial Extent: Unknown

Latitude: Unknown

Longitude: Unknown

InSAR images of Torfajokull caldera generated from SAR images acquired over the caldera from (a) 1993 to 2000 and (b) 2003 to 2007. In both cases the satellites were flying in a descending orbit, and the line-of-sight vector is to the ESE, ?21? from the vertical for (a) and ?23? for (b). Line-of-sight lengthening is seen in the western part of the volcano, and assuming that this motion is predominantly vertical gives subsidence rates of up to ?8 and ?13 mm yr?1, respectively. Black outlined star is the location of the centre of subsidence. Note difference in scale between (a) and (b).

From: Scheiber-Enslin et al. 2011.

Reference List: Scheiber-Enslin et al. 2011.

Full References:

Scheiber-Enslin, S. E., LaFemina, P. C., Sturkell, E., Hooper, A. J., & Webb, S. J., 2011. Geodetic investigation of plate spreading along a propagating ridge: the Eastern Volcanic Zone, Iceland. Geophysical Journal International, 187(3), 1175-1194..

Deformation during 1993 - 2000 [Subsidence; Observed by InSAR]

Start Date: 1993

Stop Date: 2000

Direction: Subsidence

Method: InSAR

Magnitude: Unknown

Spatial Extent: Unknown

Latitude: Unknown

Longitude: Unknown

InSAR images of Torfajokull caldera generated from SAR images acquired over the caldera from (a) 1993 to 2000 and (b) 2003 to 2007. In both cases the satellites were flying in a descending orbit, and the line-of-sight vector is to the ESE, ?21? from the vertical for (a) and ?23? for (b). Line-of-sight lengthening is seen in the western part of the volcano, and assuming that this motion is predominantly vertical gives subsidence rates of up to ?8 and ?13 mm yr?1, respectively. Black outlined star is the location of the centre of subsidence. Note difference in scale between (a) and (b).

From: Scheiber-Enslin et al. 2011.

Reference List: Scheiber-Enslin et al. 2011.

Full References:

Scheiber-Enslin, S. E., LaFemina, P. C., Sturkell, E., Hooper, A. J., & Webb, S. J., 2011. Geodetic investigation of plate spreading along a propagating ridge: the Eastern Volcanic Zone, Iceland. Geophysical Journal International, 187(3), 1175-1194..

Deformation during 1991 - 2002 [Subsidence; Observed by Tilt]

Start Date: 1991	Stop Date: 2002	Direction: Subsidence	Method: Tilt
Magnitude: Unknown	Spatial Extent: Unknown	Latitude: Unknown	Longitude: Unknown

Reference List: Sturkell et al. 2006.

Full References:

Sturkell, E., F. Sigmundsson, and R. Slunga,, 2006. 1983-2003 decaying rate of deflation at Askja caldera: Pressure decrease in an extensive magma plumbing system at a spreading plate boundary. Bull. Volc., 68, 727-735.

Emission History

There is no Emissions History data available for Torfajökull.

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 CE 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 CE "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

The following 5 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 117551-114	Unidentified	--	--
NMNH 117551-115	Unidentified	--	--
NMNH 117551-54	Unidentified	Domadalshraun Lava Field	--
NMNH 117551-55	Obsidian	Hrafntinnuhraun	--
NMNH 117551-56	Obsidian	Laugahraun lava flow	--

Affiliated Sites

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 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 Torfajökull

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).

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.

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).