On 29 March the Icelandic Meteorological Office noted that Hekla had been quiet the previous few days; no additional earthquakes had been detected since a period of increased seismicity during 10-26 March. The Icelandic Civil Defense continued to maintain a level of "uncertainty".

27 March 2013              Back to Top

On 29 March the Icelandic Meteorological Office noted that Hekla had been quiet the previous few days; no additional earthquakes had been detected since a period of increased seismicity during 10-26 March. The Icelandic Civil Defense continued to maintain a level of "uncertainty".

Sources: Icelandic Met Office

20 March 2013              Back to Top

The Icelandic Meteorological Office noted that since 10 March, at least seven micro-earthquakes at Hekla, ranging in size from M 0.4 to 1, had been detected within a small area about 4.5 km NE of the summit, at depths of 11-12 km. These earthquakes were high-frequency, suggestive of brittle fracturing rather than magma movement. At Hekla, such a clustering of earthquakes is unusual in between eruptions. Continuous measurements of borehole strain and ground-based GPS showed no changes in crustal deformation.

On 26 March the Icelandic Meteorological Office increased the Aviation Colour Code from Green to Yellow, because of the increased seismic activity. Icelandic Civil Defense together with the Police in Hvolsvöllur had also declared a level of uncertainty for Hekla, although there were no observable signs that an eruption of Hekla was imminent.

Sources: Icelandic Met Office , Icelandic National Broadcasting Service (RUV)

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

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.

Baldridge W S, McGretchin T R, Frey F A, 1973. Magmatic evolution of Heckla, Iceland. {Contr Mineral Petr}, 42: 245-258

Green J, Short N M, 1971. {Volcanic Landforms and Surface Features: a Photographic Atlas and Glossary}. New York: Springer-Verlag, 519 p

Gudmundsdottir E R, Larsen G, Eiriksson J, 2011. Two new Icelandic tephra markers: The Hekla Ö tephra layer, 6060 cal. yr BP, and Hekla DH tephra layer, ~6650 cal. yr BP. Land-sea correlation of mid-Holocene tephra markers. {The Holocene}, DOI: 10.1177/0959683610391313

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

Gudmundsson M T, Larsen G, Hoskuldsson A, Gylfason A G, 2008. Volcanic hazards in Iceland. {Jokull}, 58: 251-268

Hoskuldsson A, Oskarsson N, Pedersen R, Gronvold K, Vogfjord K, Olafsdottir R, 2007. The millennium eruption of Hekla in February 2000. {Bull Volc}, 70: 169-182

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}

Lacasse C, Karlsdottir S, Larsen G, Soosalu H, Rose W I, Ernst G G J, 2004. Weather radar observations of the Hekla 2000 eruption cloud, Iceland. {Bull Volc}, 66: 457-473

Larsen G, Eriksson J, 2008. Holocene tephra archives and tephrochronology in Iceland - a brief overview. {Jokull}, 58: 229-250

Larsen G, Thorarinsson S, 1977. H4 and other acid Hekla tephra layers. {Jokull}, 27: 1-19

Sigmarsson O, Condomines M, Fourcade S, 1992. A detailed Th, Sr and O isotope study of Hekla: differentiation processes in an Icelandic Volcano. {Contr Mineral Petr}, 112: 20-34

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

Soosalu H, Einarsson P, 2002. Earthquake activity related to the 1991 eruption of the Hekla volcano, Iceland. {Bull Volc}, 63: 536-544

Soosalu H, Einarsson P, Jakobsdottir S, 2003. Volcanic tremor related to the 1991 eruption of the Hekla volcano, Iceland. {Bull Volc}, 65: 562-577

Soosalu H, Einarsson P, Thorbjarnadottir B S, 2005. Seismic activity related to the 2000 eruption of the Hekla volcano, Iceland. {Bull Volc}, 68: 21-36

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

Thorarinsson S, 1967a. {The Eruptions of Hekla in Historical Times}. Reykjavik: Societas Scientiarum Islandica, p 1-183

Thorarinsson S, Sigvaldason G E, 1972. The Hekla eruption of 1970. {Bull Volc}, 36: 269-288

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

Tryggvason E, 1994. Observed ground deformation at Hekla, Iceland prior to and during the eruptions of 1970, 1980-81 and 1991. {J Volc Geotherm Res}, 61: 281-291

Vilmundardottir E G, Hjartarson A, 1985. Pumice flows during Hekla eruptions. {Natturufraedingurinn}, 54: 17-30 (in Icelandic with English summary)

One of Iceland's most prominent and active volcanoes, Hekla lies near the southern end of the eastern rift zone. Hekla occupies a rift-transform junction, and has produced basaltic andesites, in contrast to the tholeiitic basalts typical of Icelandic rift zone volcanoes. Vatnafjöll, a 40-km-long, 9-km-wide group of basaltic fissures and crater rows immediately SE of Hekla forms a part of the Hekla-Vatnafjöll volcanic system. A 5.5-km-long fissure, Heklugjá, cuts across the 1491-m-high Hekla volcano and is often active along its full length during major eruptions. Repeated eruptions along this rift, which is oblique to most rifting structures in the eastern volcanic zone, are responsible for Hekla's elongated ENE-WSW profile. Frequent large silicic explosive eruptions during historical time have deposited tephra throughout Iceland, providing valuable time markers used to date eruptions from other Icelandic volcanoes. Hekla tephras are generally rich in fluorine and are consequently very hazardous to grazing animals. Extensive lava flows from Hekla's historical eruptions, which date back to 1104 AD, cover much of the volcano's flanks.