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Welcome to LAVA Centre – Hekla Live Camera

Welcome to LAVA Centre – Hekla Live Camera

Hekla Volcano Profile

Elevation: 1.491 m / 4892 ft

Distance from LAVA: 24 km / 15 mi
Last Eruptions: 2000, 1991, 1980 & 1981, 1970, 1947-48, 1913

ON THE HEKLA VOLCANIC SYSTEM

Hekla is a volcanic system in southern Iceland known in medieval literature as “The gateway to Hell”. It is located at the convergence of the South Iceland Seismic Zone (SISZ) and the East Volcanic Zone (EVZ). The SISZ is a tectonic feature of lateral movement connecting two rift zones, the EVZ and the Western Volcanic Zone (WVZ), which are areas of active spreading on the plate boundary. Hekla has a central volcano (Mount Hekla) with a height of 1,491 m (4,892 ft). Mt. Hekla is at times described as a stratovolcano, although it is not a typical one, given that it has not the typical conical shape normally described for stratovolcanoes, however, it has formed by alternating explosive and effusive eruption. Hekla is commonly covered by snow and traces of glaciers are visible in two parts near the top.

In spite its location at the SISZ, seismic activity is typically none at Mt. Hekla, except some minutes prior to erupting (normally between 25 and 80 minutes before the beginning of the eruption). However, this precursory timeline may change in the near future as technology advances; with new, more sensitive, and more advanced monitoring systems, smaller earthquakes could be detected, possibly giving more warning time. Hekla, as well as all the other volcanic systems in Iceland, are constantly monitored by the Icelandic Met Office via seismographs, borehole strain meters, gps, and radar (InSAR). For more information visit:

a) University of Iceland https://earthice.hi.is/deformation_studies_hekla_volcano 

b) Icelandic Met Office https://en.vedur.is/about-imo/news/monitoring-hekla

Hekla is one of the most active volcanic systems in Iceland; having erupted over 20 times since the settlement of the country in ca. 874 CE. Since that period, Hekla has erupted once or twice every century, however, that pattern changed on the second half of the 20th century when Mt. Hekla erupted in 1947, 1970, 1980, 1981, 1991, and 2000. There are no towns in the immediate vicinity, although there are a few farms within 10 km of the top of Mount Hekla. The area surrounding Mt. Hekla is a fast-growing place for leisure, where many summer houses have been built in the last decade, and it is also regularly visited by many tourists seeking to go nearby the central volcano as they drive through the highlands towards (or from) Landmannalaugar. Furthermore, transatlantic airplane routes are often set above Hekla raising certain concern about the potential effect on air travel, in the case of an explosive eruption at Mt. Hekla. Therefore, monitoring Hekla is of outmost importance for the Icelandic authorities.

When is Hekla next eruption expected?

It is not quite possible to say with full certainty, that is why monitoring its activity is so important. Based on different monitoring techniques, we know Hekla has been ready to erupt since 2006 when the deformation level (inflation level) reached was the same as when the volcano erupted last (back in the year 2000). This deformation level suggests that a similar volume of molten material (that is, a similar amount of magma) as from the year 2000 has already entered the magma chamber under Mt. Hekla. What is definitely certain with this volcanic system is that we need to be aware that the eruption can take place soon, know how the eruption can take place, and be prepared to act accordingly (if necessary) for when the next eruption comes.

Recommended Hekla tours from LAVA Centre

Why is it spoken of a “Volcanic System”? What does this mean?

The term volcanic system indicates that eruptions can occur both at the central volcano or at the fissure swarm within the system. This is something characteristic of the Icelandic geology. Why is it important? Because not all volcanic systems possess a central volcano. The presence of a Central Volcano within a volcanic system points at the existence of a magma chamber at a certain depth, and thus the potential of producing explosive eruptions. In the case of Hekla, the precise location of the magma chamber has not been established yet, however, all points out at a fairly deep chamber. One piece of evidence is the lack of geothermal features around Mt. Hekla.

Within the Hekla volcanic system, Mt. Hekla is exemplified by mixed eruptions; this means that during an eruption both an explosive phase (i.e., large production of tephra/ash), and an effusive phase (i.e., production of lava flows) can occur at the same time, at a certain point during the eruption. During most of the recent eruptions, Hekla has shown a particular pattern when erupting from the central volcano. 

In the beginning, Mt. Hekla erupts explosively from the top of the mountain, producing a volcanic column that can reach tens of kilometers in a matter of a few minutes. When the energy of the initial stage starts to decrease, a fissure opens along the length of the mountain. This fissure is known as Heklugjá. At this point, both explosive and effusive activity coexist. However, the eruption progressively becomes exclusively effusive. How long does this stage last? It is uncertain, but normally it does not last more than a couple of hours. Once the whole length of Heklugjá is active the products of the eruption are only lava flows.

The composition of the products on the initial stage of the eruption varies quite considerably. Dacite is the most common type of rock erupted during the first stage, but Rhyolite has also occurred in historical times. Regardless of the initial composition, the lavas erupted towards the last stage of the eruption are always of a type called Basaltic Andesite. These lavas are intermediate lavas, meaning they are not as mafic (silica poor) as a basalt, but also not as felsic (silica rich) as an andesite. For more detailed information, can read Imsland (1978), Jakobsson et al. (2008), 

Hekla volcanic system can also produce eruptions outside the central volcano. In this case, the eruptions occur through fissures, and the products are purely basalts. In historical times only five (5) eruptions have been like this at the Hekla volcanic system, the most recent one took place in 1913.  

Furthermore, magmas from Hekla contain high quantities of fluorine, making the volcanic products from Hekla considerably hazardous, in particular, to farm animals. This occurs because fluorine atoms attach to tephra particles, and as tephra falls on pastures, they become contaminated (For more detailed information: Óskarsson, 1980). When animals eat large amounts of contaminated grass, they become likely to contract a condition known as fluorosis, which can have negative consequences on the teeth, bones, and organs of the animals, leading even to a painful death. So far, fluorosis associated to Hekla eruptions have not been documented on humans. 

If you are thinking about traveling to Iceland one of the most popular recommendations that you will find in the guides is the Hekla volcano. We invite you to come at Lava Centre and visit our modern exhibition, winner of several international awards, where you will find interactive information about the Hekla and other important volcanic systems in Iceland.

On the spring of 2019 we built an observation platform from which to observe the five different volcanic systems in our vicinity (weather permitting). The systems near us are Hekla, Eyjafjallajökull, Katla, Vestmannaeyjar, and Tindfjallajökull.

Come and learn about the geology of Iceland in an interactive and fun way. You can buy your tickets online at the following link LAVA Centre Tickets or at the reception, our team will be happy to welcome you! 

Iceland landscape with Hekla volcano in the background. Hekla most active volcano in Iceland

References

Imsland, P. (1978) The petrology of Iceland, some general remarks. Nordic Volcanological Institute Report, 78 08.

Jakobsson, S.; Jónasson, K. & Sigurdsson, I. (2008) The three igneous rock series of Iceland. Jökull, 58. 

Óskarsson, N. (1980) The interaction between volcanic gases and tephra: fluorine adhering to tephra of the 1970 Hekla eruption. Journal of Volcanology and Geothermal Research 8 (1980) 251 – 266.