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Katla

Google Earth Placemark
  • Country
  • Subregion Name
  • Volcano Type
  • Last Known Eruption
  • 1512 m
  • 63.630°
  • -19.050°
  • Elevation
  • Latitude
  • Longitude

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.



 Available Weekly Reports


All times are local (= UTC - 9 hours [or 8 hours early April-late October])

2011: July | October |

12 October 2011            Back to Top

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.

Sources: Icelandic Met Office

6 July 2011            Back to Top

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: Iceland Review , Icelandic Met Office , Morgunbladid News



Below is a summary of eruption dates and Volcanic Explosivity Indices (VEI).


Start Date (mm/dd/yyyy)
Stop Date (mm/dd/yyyy)
VEI
7/17/1999
8/15/1999
0
6/25/1955
0/0/
0
10/12/1918
11/4/1918
4
5/8/1860
5/27/1860
4
6/26/1823
7/23/1823
3
10/17/1755
2/13/1756
5
5/11/1721
10/15/1721
5
11/3/1660
0/0/1661
4
9/2/1625
9/14/1625
5
10/12/1612
0/0/
4
8/11/1580
0/0/
4
0/0/1550
0/0/
4
0/0/1500
0/0/
4
0/0/1450
0/0/
0/0/1440
0/0/
4
0/0/1416
0/0/
4
0/0/1357
0/0/
4
1/18/1311
0/0/
0/0/1262
0/0/
5
0/0/1245
0/0/
4
0/0/1210
0/0/
4
0/0/1177
0/0/
3
0/0/1150
0/0/
0/0/1000
0/0/
0/0/960
0/0/
3
0/0/950
0/0/
0/0/934
0/0/940
4
0/0/920
0/0/
4
0/0/904
0/0/
0/0/820
0/0/
0/0/780
0/0/
0/0/680
0/0/
0/0/610
0/0/
0/0/590
0/0/
0/0/540
0/0/
0/0/500
0/0/
0/0/400
0/0/
0/0/290
0/0/
0/0/270
0/0/
3
0/0/260
0/0/
0/0/200
0/0/
0/0/130
0/0/
0/0/30
0/0/
0/0/-80
0/0/
0/0/-250
0/0/
0/0/-370
0/0/
0/0/-430
0/0/
0/0/-530
0/0/
0/0/-550
0/0/
0/0/-560
0/0/
0/0/-600
0/0/
0/0/-650
0/0/
0/0/-700
0/0/
0/0/-740
0/0/
0/0/-780
0/0/
0/0/-850
0/0/
4
0/0/-860
0/0/
0/0/-920
0/0/
0/0/-990
0/0/
0/0/-1160
0/0/
0/0/-1190
0/0/
0/0/-1220
0/0/
3
0/0/-1280
0/0/
0/0/-1290
0/0/
0/0/-1440
0/0/
4
0/0/-1540
0/0/
0/0/-1640
0/0/
0/0/-1670
0/0/
0/0/-1700
0/0/
0/0/-1850
0/0/
0/0/-1910
0/0/
0/0/-1920
0/0/
4
0/0/-1950
0/0/
0/0/-2000
0/0/
0/0/-2020
0/0/
0/0/-2050
0/0/
0/0/-2110
0/0/
0/0/-2160
0/0/
0/0/-2190
0/0/
0/0/-2220
0/0/
0/0/-2250
0/0/
0/0/-2420
0/0/
0/0/-2480
0/0/
0/0/-2540
0/0/
0/0/-2680
0/0/
0/0/-2850
0/0/
0/0/-2920
0/0/
3
0/0/-3180
0/0/
0/0/-3280
0/0/
0/0/-3370
0/0/
0/0/-3390
0/0/
0/0/-3480
0/0/
0/0/-3510
0/0/
0/0/-3640
0/0/
0/0/-3670
0/0/
0/0/-3720
0/0/
0/0/-3790
0/0/
0/0/-3810
0/0/
0/0/-3930
0/0/
0/0/-4060
0/0/
0/0/-4210
0/0/
0/0/-4240
0/0/
0/0/-4280
0/0/
0/0/-4370
0/0/
0/0/-4430
0/0/
0/0/-4610
0/0/
0/0/-4660
0/0/
0/0/-4750
0/0/
0/0/-4810
0/0/
0/0/-4880
0/0/
0/0/-5020
0/0/
0/0/-5040
0/0/
0/0/-5070
0/0/
0/0/-5180
0/0/
0/0/-5230
0/0/
0/0/-5360
0/0/
0/0/-5460
0/0/
0/0/-5470
0/0/
0/0/-5550
0/0/
0/0/-5560
0/0/
0/0/-5630
0/0/
0/0/-5710
0/0/
0/0/-5720
0/0/
0/0/-5730
0/0/
0/0/-5850
0/0/
0/0/-5890
0/0/
0/0/-5960
0/0/
0/0/-6050
0/0/
0/0/-6170
0/0/
0/0/-6200
0/0/
0/0/-6230
0/0/
0/0/-6380
0/0/

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. 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. Additional discussion of data sources can be found under Volcano Data Criteria.

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



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 AD 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.