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  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 63.63°N
  • 19.05°W

  • 1512 m
    4959 ft

  • 372030
  • Latitude
  • Longitude

  • Summit

  • Volcano

12 October-18 October 2011

The Iceland Met Office reported increased seismic activity within Katla's caldera. Unrest was first noted in July, when a short-lived glacial flood burst from the Myrdalsjökull glacier that covers Katla occurred in connection with increased seismicity. Since then, several hundred micro-earthquakes had taken place within the area of the caldera. On 5 October an intense earthquake swarm was detected. Most of the earthquakes originated at 5 km depth; the largest one was approximately a M 3.7.

Source: Icelandic Met Office

Index of Weekly Reports

2011: July | October

Weekly Reports

12 October-18 October 2011

The Iceland Met Office reported increased seismic activity within Katla's caldera. Unrest was first noted in July, when a short-lived glacial flood burst from the Myrdalsjökull glacier that covers Katla occurred in connection with increased seismicity. Since then, several hundred micro-earthquakes had taken place within the area of the caldera. On 5 October an intense earthquake swarm was detected. Most of the earthquakes originated at 5 km depth; the largest one was approximately a M 3.7.

Source: Icelandic Met Office

6 July-12 July 2011

The Iceland Met Office and news sources reported that on 9 July a jökulhlaup from Myrdalsjökull, the ice sheet that covers Katla, originated from three ice cauldrons in the SE part of the caldera. During previous weeks microseismicity had been registered near several of the ice cauldrons. Around the time of peak harmonic tremor, in the early evening on 8 July, the Myrdalsjökull flood monitoring system indicated increased conduction. The water level reached the bridge around midnight and damaged the sensors. According to news articles, one new cauldron that had formed, along with cracks in the glacier around the cauldrons, may have been caused by a small eruption at Katla although no evidence of an eruption was observed. The jökulhlaup had destroyed a 128-m-long bridge and caused damage, resulting in the closing of part of the Ring Road. About 200 people were evacuated from the area but allowed to return home later that day. On 10 July the water had subsided and returned to normal levels.

Sources: Icelandic Met Office; Morgunbladid News; Iceland Review; Iceland Review; Iceland Review

Index of Monthly Reports

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

11/1977 (SEAN 02:11) Annual seismic energy release, 1970-September 1977

09/1999 (BGVN 24:09) Tremor in mid-July followed by a jökulhlaup and ice cauldron formation

11/2011 (BGVN 36:11) Jökulhlaup and elevated seismicity in 2011; filming sparks eruption fears

Contents of Monthly Reports

All information contained in these reports is preliminary and subject to change.

11/1977 (SEAN 02:11) Annual seismic energy release, 1970-September 1977

Figure 1 shows annual seismic strain release from 1970-September 1977 in the Myrdalsjökull area. After 1977, the annual strain release was similar to that of 1970-74.

Figure 1. Annual seismic strain release in the Myrdalsjökull area, February 1970 through September 1977. From Skjálftabref (published by the Icelandic Meteorological Office, no. 26, October 1977. Courtesy of Ragnar Stefánsson.

Information Contact: R. Stefánsson, Icelandic Meteorological Office.

09/1999 (BGVN 24:09) Tremor in mid-July followed by a jökulhlaup and ice cauldron formation

In the early morning of 18 July, a small jökulhlaup (sudden glacier-outburst flood) lasting less than 24 hours, occurred in "Jökulsá á Sólheimasandi," one of the rivers draining from the Mýrdalsjökull icecap (figure 2) towards the S. Inspection of the icecap revealed that a new ice cauldron, ~2 km wide, and 50 m deep, had formed just above the origin of the Sólheimajökull outlet glacier. The jökulhlaup was preceded on 17 July by a 20-minute-long burst of modest volcanic tremor (reported by P. Einarsson). Intrusion of magma at a low level within the subglacial Katla volcano or even a small subglacial eruption may have occurred, possibly associated with pulse of CO2 which could have caused boiling in geothermal areas under the icecap.

Figure 2. Topographic map of the Mýrdalsjökull icecap over Katla volcano showing tilt stations. Courtesy of the Nordisk Vulkvanologisk Institut.

From 18 July until mid-August, ten new ice cauldrons formed along the W, S, and E borders of the Mýrdalsjökull caldera (figure 3), signifying increased geothermal activity along a large part of the caldera rim. Changes on the icecap surface have been reported for some of the earlier eruptions of Katla, and the current activity could be a possible long-term precursor to a new eruption. A flight over the area on 9 September by Reynir Ragnarsson at Vík, revealed that the ice cauldrons did not develop much after mid-August.

Figure 3. One of the new ice cauldrons on Mýrdalsjökull, July-August 1999. Photo by Freysteinn Sigmundsson.

Information Contacts: Rósa Ólafsdóttir (rosa@norvol.hi.is), Guðrún Sverrisdóttir (gsv@norvol.hi.is), Freysteinn Sigmundsson (fs@norvol.hi.is), Erik Sturkell (erik@norvol.hi.is), and Níels Óskarsson (niels@norvol.hi.is), Nordisk Vulkvanologisk Institut, Grenásvegur 50, 108 Reyjavík, Iceland (URL: http://www.norvol.hi.is); Helgi Björnsson (hb@raunvis.hi.is), Páll Einarsson (palli@raunvis.hi.is), and Magnús Tumi Guðmundsson (mtg@raunvis.hi.is), Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavík, Iceland (URL: http://www.raunvis.hi.is/RaunvisHomeE.html); Ármann Höskuldsson (arm@eyjar.is), South Iceland Institute of Natural History, Strandvegur 50, 900 Vestmannaeyjar, Iceland (URL: http://www.nattsud.is/nshomeuk.htm).

11/2011 (BGVN 36:11) Jökulhlaup and elevated seismicity in 2011; filming sparks eruption fears

Microseismicity preceded and accompanied a jökulhlaup (a glacier-outburst flood) on 9 July 2011, as reported by the Iceland Met Office (IMO). The jökulhlaup escaped from under Mýrdalsjökull, the glacier that rests above Iceland's Katla volcano, its 10 x 14 km caldera, and environs (figure 38). IMO reported that microseismicity was registered near several ice cauldrons in the caldera for a few weeks prior to the event (figure 39). Peak harmonic tremor on 8 July coincided with rising water levels and increased water conductivity, as measured by the main flood gauge (figure 40; gauge is at red triangle on figure 38).

Figure 38. A map of road closures and restricted areas of Mýrdalsjökull glacier resulting from the 9 July 2011 jökulhlaup at Katla (see key, lower left). The town of Vík is shown near the bottom (in black), and the main road through the area is shown in red; the trace of Katla caldera is shown in black and labeled. The main flood gauge was on the bridge across the Múlakvísl river; both were destroyed in the jökulhlaup event (red triangle). Inset shows the geographic location of Katla and Mýrdalsjökull in the S of Iceland. Restricted areas map modified from ágúst Gunnar Gylfason of the National Commissioner of the Icelandic Police-Department of Civil Protection and Emergency Management; index map modified from Ginkgo Maps.
Figure 39. Map (top) and plot (bottom) of the seismicity recorded during 8-9 July 2011 at Katla. Colors indicate the timing of epicenters and their respective plotted magnitudes, recorded as late as 2250 on 9 July 2011, according to the scheme shown below the map. Black triangles indicate seismic monitoring stations. Courtesy of Iceland Met Office (IMO).
Figure 40. Running plots of (a) water level, (b) water temperature, and (c) water conductivity at the main flood gauge of the Múlakvísl river during 3-9 July 2011. The plots show rising water level and conductivity that were coincident with peak harmonic tremor. The plots stop abruptly (red vertical line) when the gauge was destroyed along with the bridge crossing the Múlakvísl river. Courtesy of Iceland Met Office (IMO).

IMO reported that, on the same day, the main flood gauge was damaged when flood waters reached the instrument near midnight; another station, normally not in the water, started recording rising water around 0400 on 9 July, and the water level there rose 5 m within 5 minutes (figure 41). When the flood reached the main road approximately one hour later, the main bridge over the Múlakvísl river was destroyed and the road was closed (red triangle, figure 41).

Figure 41. A running plot of water level at the second flood gauge (normally not submerged). The plot shows a significant rise in water level (5 m within 5 minutes). Courtesy of Iceland Met Office (IMO).

According to the news source Morgunblaðið, 200 people were safely evacuated, and allowed to return to their homes by that afternoon. Morgunblaðið reported that analysis of the flood waters indicated that the flood was caused by geothermal water, but that a sub-glacial eruption at Katla could not be ruled out. IMO stated that the harmonic tremor declined on 9 July, following the jökulhlaup event. After observational flights, new cracks and cauldrons were reported in the ice of Mýrdalsjökull glacier (figure 42).

Figure 42. Cracking and subsidence of the Mýrdalsjökull glacier around an ice cauldron above the Katla caldera. Widespread gray tephra deposited on the ice surface is due to the 2010 Eyjafjallajökull eruption (BGVN 35:03, 35:04). Courtesy of the Icelandic Coast Guard.

By 16 July, the National Commissioner of Icelandic Police in the Department of Civil Protection and Emergency Management reported that a new bridge had been built to replace the bridge destroyed in the jökulhlaup (figure 43).

Figure 43. Photograph of the remains of the bridge crossing of the Múlakvísl river, destroyed in the jökulhlaup event on 9 July 2011. The new bridge, constructed by the 16 July 2011, can be seen in the background. Courtesy of John A. Stevenson.

August-December seismicity. IMO reported increased seismicity under Mýrdalsjökull in October (figure 44). They reported that 512 earthquakes occurred, with ~ 380 originating within the Katla caldera; a large portion (nearly 100) of those 512 earthquakes occurred on one day near the beginning of October (figure 45). The largest reported earthquake was M 4, with seven being larger than M 3. On 8 November, an M 3.2 earthquake that originated in the S most part of the caldera was felt by residents in the town of Vík.

Overall, following the July 2011 jökulhlaup event, seismicity has increased above background levels of the past year. The seismic peak is noticeable with respect to the number of earthquakes, their largest magnitudes, and the clustering under Katla (figures 44 and 45). The largest earthquakes were as large, or slightly larger, than the other earthquakes of M 3 or greater in earlier episodes of unrest (i.e., 1999 and 2002-2004, figure 44). The bulk of the 2011 seismic increase occurred over a shallow depth range (within 4 km of the surface, figure 46).

Figure 44. Plots of seismicity (greater than M 0.6) at Katla since 1999, showing the October 2011 seismicity in comparison with past episodes of non-eruptive unrest, such as in 1999 (sub-glacial eruption is uncertain in the GVP database) and 2002-2004. Plots (from the top) show: the monthly number of earthquakes (log scale); the magnitudes of earthquakes; cumulative number of earthquakes (red) and cumulative seismic moment (blue); and the focal depths of the located earthquakes. Courtesy of Iceland Met Office (IMO).
Figure 45. Seismic events (stronger than M 0.5) per day at Katla during December 2010-December 2011. Raw data is shown in blue, the 5 day moving average is shown in red, and events stronger than M 3.0 are indicated by gold stars. These trends highlight the increased seismicity of August-December 2011. Courtesy of the University of Edinburgh School of Geosciences.
Figure 46. Cumulative number of seismic events (stronger than M 0.5) at Katla since 23 November 2010. All events are shown in yellow, and events originating at depths greater than 4 and 10 km are shown in orange and red, respectively. During the August-December 2011 increase in seismicity, the majority of the recorded events originated from shallow depths (less than 4 km). Courtesy of the University of Edinburgh School of Geosciences.

Television filming sparks eruption fears. The Iceland Review reported that, in the early morning of 9 December, the Icelandic emergency hotline received calls from residents reporting bright lights on the slopes of Mýrdalsjökull. Callers feared that an eruption had started at Katla. The bright lights had also been noticed on a webcam by observers in Norway, who also enquired if there was an eruption. When the glacial slopes were inspected to find the cause of the lights, it was discovered that they were from film crews for the HBO series "Game of Thrones", who were filming in the early morning to capture the desired light conditions.

Information Contacts: Einar Kjartansson, Iceland Met Office (IMO), Bústaðavegi 9, 150 Reykjavík, Iceland (URL: http://en.vedur.is/); National Commissioner of the Icelandic Police-Department of Civil Protection and Emergency Management, Skúlagata 21, 101 Reykjavík, Iceland (URL: http://www.almannavarnir.is/); Ginkgo Maps (URL: http://ginkgomaps.com/); Morgunblaðið, Hádegismóum 2, 110 Reykjavík, Iceland (URL: http://mbl.is/); Icelandic Coast Guard, Skógarhlíð 14, 105 Reykjavík, Iceland (URL: http://www.lhg.is/); John A. Stevenson (URL: http://all-geo.org/volcan01010/); The University of Edinburgh School of Geosciences (URL: http://www.ed.ac.uk/schools-departments/geosciences); The Iceland Review, Borgartúni 23, 105 Reykjavík, Iceland (URL: http://www.icelandreview.com/).

Katla volcano, located near the southern end of Iceland's eastern volcanic zone, is hidden beneath the Myrdalsjökull icecap. The subglacial basaltic-to-rhyolitic volcano is one of Iceland's most active and is a frequent producer of damaging jökulhlaups, or glacier-outburst floods. A large 10 x 14 km subglacial caldera with a long axis in a NW-SE direction is up to 750 m deep. Its high point reaches 1380 m, and three major outlet glaciers have breached its rim. Although most historical eruptions have taken place from fissures inside the caldera, the Eldgjá fissure system, which extends about 60 km to the NE from the current ice margin towards Grímsvötn volcano, has been the source of major Holocene eruptions. An eruption from the Eldgjá fissure system about 934 CE produced a voluminous lava flow of about 18 cu km, one of the world's largest known Holocene lava flows. Katla has been the source of frequent subglacial basaltic explosive eruptions that have been among the largest tephra-producers in Iceland during historical time and has also produced numerous dacitic explosive eruptions during the Holocene.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
[ 1999 Jul 17 (?) ] [ 1999 Aug 15 ± 5 days ] Uncertain 0   W, S, and E margins of caldera
[ 1955 Jun 25 ] [ Unknown ] Uncertain 0   East side of caldera
1918 Oct 12 1918 Nov 4 Confirmed 4 Historical Observations South side of caldera, K-1918
1860 May 8 1860 May 27 Confirmed 4 Historical Observations
1823 Jun 26 1823 Jul 23 Confirmed 3 Historical Observations Arcuate fissure in south part of caldera
1755 Oct 17 1756 Feb 13 Confirmed 5 Historical Observations E-W fissure in center of caldera
1721 May 11 1721 Oct 15 ± 45 days Confirmed 5 Historical Observations
1660 Nov 3 1661 Confirmed 4 Historical Observations
1625 Sep 2 1625 Sep 14 Confirmed 5 Historical Observations
1612 Oct 12 Unknown Confirmed 4 Historical Observations
1580 Aug 11 Unknown Confirmed 4 Historical Observations
1550 (?) Unknown Confirmed 4 Tephrochronology
1500 (?) Unknown Confirmed 4 Tephrochronology
1450 ± 50 years Unknown Confirmed   Tephrochronology
1440 Unknown Confirmed 4 Historical Observations
1416 Unknown Confirmed 4 Historical Observations
1357 ± 3 years Unknown Confirmed 4 Historical Observations SW of Kotlugja
1311 Jan 18 Unknown Confirmed   Historical Observations
1262 Unknown Confirmed 5 Historical Observations
1245 Unknown Confirmed 4 Historical Observations
1210 (?) Unknown Confirmed 4 Tephrochronology
1177 ± 2 years Unknown Confirmed 3 Historical Observations
1150 ± 50 years Unknown Confirmed   Tephrochronology
[ 1000 (?) ] [ Unknown ] Discredited    
0960 (?) Unknown Confirmed 3 Tephrochronology
0950 (?) Unknown Confirmed   Tephrochronology
0934 ± 2 years 0940 (?) Confirmed 4 Ice Core Eldgjá fissure system (NE flank)
0920 Unknown Confirmed 4 Historical Observations
[ 0904 (?) ] [ Unknown ] Uncertain    
0820 (?) Unknown Confirmed   Tephrochronology
0780 (?) Unknown Confirmed   Tephrochronology
0680 (?) Unknown Confirmed   Tephrochronology
0610 (?) Unknown Confirmed   Tephrochronology
0590 (?) Unknown Confirmed   Tephrochronology
0540 (?) Unknown Confirmed   Tephrochronology
0500 (?) Unknown Confirmed   Tephrochronology
0400 (?) Unknown Confirmed   Tephrochronology
0290 (?) Unknown Confirmed   Tephrochronology
0270 ± 12 years Unknown Confirmed 3 Radiocarbon (uncorrected) Tephra layer YN
0260 (?) Unknown Confirmed   Tephrochronology
0200 (?) Unknown Confirmed   Tephrochronology
0130 (?) Unknown Confirmed   Tephrochronology
0030 (?) Unknown Confirmed   Tephrochronology
0080 BCE (?) Unknown Confirmed   Tephrochronology
0250 BCE (?) Unknown Confirmed   Tephrochronology
0370 BCE (?) Unknown Confirmed   Tephrochronology
0430 BCE (?) Unknown Confirmed   Tephrochronology
0530 BCE (?) Unknown Confirmed   Tephrochronology
0550 BCE (?) Unknown Confirmed   Tephrochronology
0560 BCE (?) Unknown Confirmed   Tephrochronology
0600 BCE (?) Unknown Confirmed   Tephrochronology
0650 BCE (?) Unknown Confirmed   Tephrochronology
0700 BCE (?) Unknown Confirmed   Tephrochronology
0740 BCE (?) Unknown Confirmed   Tephrochronology
0780 BCE (?) Unknown Confirmed   Tephrochronology
0850 BCE ± 50 years Unknown Confirmed 4 Radiocarbon (corrected) Tephra layer UN
0860 BCE (?) Unknown Confirmed   Tephrochronology
0920 BCE (?) Unknown Confirmed   Tephrochronology
0990 BCE (?) Unknown Confirmed   Tephrochronology
1160 BCE (?) Unknown Confirmed   Tephrochronology
1190 BCE (?) Unknown Confirmed   Tephrochronology
1220 BCE ± 12 years Unknown Confirmed 3 Radiocarbon (corrected) Tephra layer MN
1280 BCE (?) Unknown Confirmed   Tephrochronology
1290 BCE (?) Unknown Confirmed   Tephrochronology
1440 BCE ± 40 years Unknown Confirmed 4 Radiocarbon (corrected) Tephra layer LN
1540 BCE (?) Unknown Confirmed   Tephrochronology
1640 BCE (?) Unknown Confirmed   Tephrochronology
1670 BCE (?) Unknown Confirmed   Tephrochronology
1700 BCE (?) Unknown Confirmed   Tephrochronology
1850 BCE (?) Unknown Confirmed   Tephrochronology
1910 BCE (?) Unknown Confirmed   Tephrochronology
1920 BCE (?) Unknown Confirmed 4 Radiocarbon (corrected) Tephra layer N4
1950 BCE (?) Unknown Confirmed   Tephrochronology
2000 BCE (?) Unknown Confirmed   Tephrochronology
2020 BCE (?) Unknown Confirmed   Tephrochronology
2050 BCE (?) Unknown Confirmed   Tephrochronology
2110 BCE (?) Unknown Confirmed   Tephrochronology
2160 BCE (?) Unknown Confirmed   Tephrochronology
2190 BCE (?) Unknown Confirmed   Tephrochronology
2220 BCE (?) Unknown Confirmed   Tephrochronology
2250 BCE (?) Unknown Confirmed   Tephrochronology
2420 BCE (?) Unknown Confirmed   Tephrochronology
2480 BCE (?) Unknown Confirmed   Tephrochronology
2540 BCE (?) Unknown Confirmed   Tephrochronology
2680 BCE (?) Unknown Confirmed   Tephrochronology
2850 BCE (?) Unknown Confirmed   Tephrochronology
2920 BCE (?) Unknown Confirmed 3 Tephrochronology Tephra layer N2
3180 BCE (?) Unknown Confirmed   Tephrochronology
3280 BCE (?) Unknown Confirmed   Tephrochronology
3370 BCE (?) Unknown Confirmed   Tephrochronology
3390 BCE (?) Unknown Confirmed   Tephrochronology
3480 BCE (?) Unknown Confirmed   Tephrochronology
3510 BCE (?) Unknown Confirmed   Tephrochronology
3640 BCE (?) Unknown Confirmed   Tephrochronology
3670 BCE (?) Unknown Confirmed   Tephrochronology
3720 BCE (?) Unknown Confirmed   Tephrochronology
3790 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer N1
3810 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer A1
3930 BCE (?) Unknown Confirmed   Tephrochronology
4060 BCE (?) Unknown Confirmed   Tephrochronology
4210 BCE (?) Unknown Confirmed   Tephrochronology
4240 BCE (?) Unknown Confirmed   Tephrochronology
4280 BCE (?) Unknown Confirmed   Tephrochronology
4370 BCE (?) Unknown Confirmed   Tephrochronology
4430 BCE (?) Unknown Confirmed   Tephrochronology
4610 BCE (?) Unknown Confirmed   Tephrochronology
4660 BCE (?) Unknown Confirmed   Tephrochronology
4750 BCE (?) Unknown Confirmed   Tephrochronology
4810 BCE (?) Unknown Confirmed   Tephrochronology
4880 BCE (?) Unknown Confirmed   Tephrochronology
5020 BCE (?) Unknown Confirmed   Tephrochronology
5040 BCE (?) Unknown Confirmed   Tephrochronology
5070 BCE (?) Unknown Confirmed   Tephrochronology
5180 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer A7
5230 BCE (?) Unknown Confirmed   Tephrochronology
5360 BCE (?) Unknown Confirmed   Tephrochronology
5460 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer A8
5470 BCE (?) Unknown Confirmed   Tephrochronology
5550 BCE (?) Unknown Confirmed   Tephrochronology NE flank
5560 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer A9
5630 BCE (?) Unknown Confirmed   Tephrochronology
5710 BCE (?) Unknown Confirmed   Tephrochronology
5720 BCE (?) Unknown Confirmed   Tephrochronology
5730 BCE (?) Unknown Confirmed   Tephrochronology
5850 BCE (?) Unknown Confirmed   Tephrochronology
5890 BCE (?) Unknown Confirmed   Tephrochronology
5960 BCE (?) Unknown Confirmed   Tephrochronology
6050 BCE (?) Unknown Confirmed   Tephrochronology
6170 BCE (?) Unknown Confirmed   Tephrochronology
6200 BCE (?) Unknown Confirmed   Tephrochronology
6230 BCE (?) Unknown Confirmed   Tephrochronology
6380 BCE (?) Unknown Confirmed   Tephrochronology

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.

Kotlugja | Katlogiaa | Koetlegiaa | Myrdalsjokull | Midhdalsjokull | Hoefdhajokull | Soelheimajokull

Feature Name Feature Type Elevation Latitude Longitude
Myrdalsjökull Stratovolcano 1450 m 63° 53' 0" N 18° 46' 0" W

Feature Name Feature Type Elevation Latitude Longitude
Alftakvislarhraun Fissure vent 63° 46' 0" N 18° 50' 0" W
Almenningahraun Fissure vent 63° 44' 0" N 19° 22' 0" W
Brytalaekir Fissure vent 778 m 63° 50' 0" N 18° 51' 0" W
Eldgjá Fissure vent 800 m 63° 53' 0" N 18° 46' 0" W
Emstruhruan Fissure vent 63° 47' 0" N 19° 14' 0" W
Fljotahraun Fissure vent 63° 45' 0" N 19° 19' 0" W
Krikahraun Fissure vent 63° 36' 0" N 18° 50' 0" W
Maelifellshraun Fissure vent 63° 48' 0" N 19° 12' 0" W
Midkvislarhraun Fissure vent 63° 37' 0" N 18° 50' 0" W
Raudibotn Crater 720 m 63° 51' 0" N 18° 50' 0" W
Tuddahraun Fissure vent 63° 46' 0" N 19° 22' 0" W
Vedurhalshraun Fissure vent 678 m 63° 49' 0" N 19° 0' 0" W
Katla volcano, located near the southern end of Iceland's eastern volcanic zone, is mostly hidden beneath the Myrdalsjökull icecap, which extends across the top of the photo. Valley glaciers descend from the summit icecap toward the coastal plain in this aerial view from the SSW. Explosive eruptions from Katla, among the largest tephra-producers in Iceland during historical time, have frequently been accompanied by damaging jökulhlaups, or glacier-outburst floods.

Photo by Oddur Sigurdsson, 1985 (Icelandic National Energy Authority).

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.

Bjornsson H, Palsson F, Gudmundsson M T, 2000. Surface and bedrock topography of the Myrdalsjokull ice cap, Iceland: the Katla caldera, eruptions sites and routes of jokulhlaups. Jokull, 49: 29-46.

Einarsson E H, Larsen G, Thorarinsson S, 1980. The Solheimar tephra layer and the Katla eruption of ca. 1357. Acta Nat Islandica, 3: 1-24.

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

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.

Jonsson J, 1987. The Eldgjar eruption and the Landbrot lava. Natturufraedingurinn, 57: 1-20 (in Icelandic with English summary).

Lacasse C, Garbe-Schonberg C-D, 2001. Explosive silicic volcanism in Iceland and the Jan Mayen area during the last 6 Ma: sources and timing of major eruptions. J Volc Geotherm Res, 107: 113-147.

Lacasse C, Sigurdsson H, Carey S N, Johannesson H, Thomas L E, Rogers N W, 2007. Bimodal volcanism at the Katla subglacial caldera, Iceland: insight into the geochemistry and petrogenesis of rhyolitic magmas. Bull Volc, 69: 373-399.

Lacasse C, Sigurdsson H, Johannesson H, Paterne M, Carey S, 1995. Source of Ash Zone 1 in the North Atlantic. Bull Volc, 57: 18-32.

Larsen G, 2000. Holocene eruptions within the Katla volcanic system, south Iceland: characteristics and environmental impact. Jokull, 49: 1-28.

Larsen G, 1979. The age of Eldgja lavas. Natturufraedingurinn, 49: 1-26 (in Icelandic with English summary).

Larsen G, Newton A J, Dugmore A J, Vilmundardottir E G, 2001. Geochemistry, dispersal, volumes and chronology of Holocene silicic tephra layers from the Katla volcanic system, Iceland. J Quat Sci, 16: 119-132.

Newhall C G, Dzurisin D, 1988. Historical unrest at large calderas of the world. U S Geol Surv Bull, 1855: 1108 p, 2 vol.

Oladottir B A, Larsen G, Thordarson T, Sigmarsson O, 2005. The Katla volcano S-Iceland: Holocene tephra stratigraphy and eruption frequency. Jokull, 55: 53-74.

Oladottir B A, Sigmarsson O, Larsen G, Thordarson T, 2008. Katla volcano, Iceland: magma composition, dynamics and eruption frequency as recorded by Holocene tephra layers. Bull Volc, 70: 475-493.

Scharrer K, Spieler O, Mayer C, Munzer U, 2008. Imprints of sub-glacial volcanic activity on a glacier surface--SAR study of Katla volcano, Iceland. Bull Volc, 70: 495-506.

Soosalu H, Jonsdottir K, Einarsson P, 2006. Seismicity crisis at the Katla volcano, Iceland--signs of a cryptodome?. J Volc Geotherm Res, 153: 177-186.

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

Thorarinsson S, 1975. Katla and the annal of Katla eruptions. Arbok Ferdafelags Islands 1975, p 125-149.

Thordarson T, Hoskuldsson A, 2008. Postglacial eruptions in Iceland. Jokull, 58: 197-228.

Thordarson T, Miller D J, Larsen G, Self S, Sigurdsson H, 2001. New estimates of sulfur degassing and atmospheric mass-loading by the 934 AD Eldgja eruption. J Volc Geotherm Res, 107: 33-54.

Volcano Types

Fissure vent(s)

Tectonic Setting

Rift zone
Oceanic crust (< 15 km)

Rock Types

Basalt / Picro-Basalt
Andesite / Basaltic Andesite


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

Affiliated Databases

Large Eruptions of Katla 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.