What's happening with Hekla?
With speculation that an eruption of Mt Hekla could be imminent, Discover the World asked expert volcanologist and geophysicist Ari Trausti Guðmundsson to explain further.
In 2010, an old and not very active Icelandic volcano Eyjafjallajökull became a (somewhat unpronounceable) household name in the UK. There are, however, much more active and infamous volcanoes in the country. One of the most studied, and most prolific ones, is Hekla. The somewhat ridge-shaped mountain stands northeast of the flat, southern lowlands, at almost 1,500m above sea level. It is made of andesitic lava flows and airborne volcanic material (tephra), and the crest is lined with large and small craters of different ages.
Hekla's history stretches back thousands of years with over 20 eruptions since 1104 when the volcano woke up after a rather long repose and caused substantial damage. Hekla is an activity centre of a volcanic system which is 40-50km long and about 7km wide, and has a number of volcanic fissures. Underneath Hekla and its volcanic system, an elongated magma chamber resides about 7-8km down. Hekla has so far been the most productive volcano in Iceland during the Holocene (the current geological epoch) with some 33km3 of eruptives added to its bulk. There are at least 27 basalt volcanic units outside of Hekla and a further 70-100 units if intermediate and acid tephra layers (and associated lava flows) from Hekla are included.
It is a well-known fact that Hekla’s eruptions tend to be more explosive the longer the dormant period gets to be. The eruption in 1104 mainly produced widespread ash and pumice. During the period from the 12th century to 1947, the norm became one or two eruptions every century and their effects were quite heavy at times. The eruption in 1947-1948 spread ash to Northern Europe and would have had substantial effects on modern air traffic in the region.
After a rather small lava and tephra eruption in 1970, Hekla changed her mood (the name ‘Hekla’ is female and so is the mountain in the eyes of Icelanders) and erupted once every decade, in 1980/81, 1991 and 2000. These eruptions were also of this mixed type, strong for one or two days but rapidly declining and lasted only a few weeks each with small or moderate effects on the surroundings. The lava flows hardly reached the base of the mountain and the tephra did not cover large areas with tick deposits. International flight traffic was not affected and many people were able to observe the development close up to the mountain.
How is Hekla monitored?
Various processes and parameters at Hekla are being studied. The seismic activity is monitored and bedrock strain in boreholes measured, a number of GPS-stations show inflation of the mountain and volcanic gasses are monitored, just to mention the main fields of research, besides basic geological and geophysical studies.
At present, the inflation overrides the values prior to the eruption in 2000 and small scale earthquake activity has slightly increased. Nothing indicates an imminent eruption; however, clear preludes to the latest Hekla eruptions are very short, in the order of only 1-2 hours.
There are at least three different scenarios to consider. Hekla could erupt in the same manner as, for example, in 2000 within a timespan of weeks, some months or a few years. In that case, the effects on mainland Europe through the ash plume would almost certainly be negligible. A longer dormant period, with more magma influx, might delay an eruption for a few decades and this could produce a more powerful eruption with effects hard to forecast. So whilst it’s impossible to predict when exactly the eruption will occur, volcanologists will probably agree that you can never trust a dormant volcano and certainly can never foresee its activity with too much accuracy.
About the expert
Ari Trausti Guðmundsson is a lecturer and writer in the fields of geology, volcanology, astronomy, environmental science and mountaineering, with close to 40 published book titles. Educated as a geophysicist in Norway and Iceland, Ari Trausti works as a freelance consultant in the fields of geoscience, tourism and environmental issues as well as writing and hosting numerous radio and television programs and documentaries. Ari Trausti is also noted as an avid mountaineer, Arctic traveller and is an international member of the Explorers Club. He contributes to scientific exhibitions, visitors' centers and museums in Iceland and abroad and received prizes for communication in science in 2007 and 2010.
Discover the World's Travel Disruption Charter
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A brand new exciting resources website created for geography teachers by Discover the World Education and the Geographical Association to be launched by April 14th.
The site will be developed over the coming years. Initially, we will be offering you resources relating to Iceland. Later in 2014 you will find material on Norway, Azores and China. In early 2015 we plan to develop resources relating to Italy and beyond.
It doesn’t stop there; other benefits and features include:
- Free access for teaching professionals
- Opportunity to share your own resources and to receive payment for your work.
- Enter your students into the Outstanding Geography Student Award to be in with a chance of winning a school trip abroad.
- Regular geographical news feeds and geography debates relating to Discover the World Education destinations.
- Information on free and discounted continuous professional development courses for teachers.
- Teacher forum allowing you to share ideas, ask questions and make suggestions on existing and future resources.
- Opportunity to win a trip to Iceland for the best teacher contributions.
- Includes the multi award winning Discover the World Education study aids featuring Eyjafjallajokull, Solheimajokull and tourism in Hardanger, Norway.
- Includes the award winning Mission:Explore Iceland resources
Sign up to our monthly enews letter to be notified of its launch date.
The Blue Lagoon - does it live up to the hype?
Few would argue that the Blue Lagoon offers a unique and special experience. Set amidst a field of black basalt lava, the temperature averages 35-40°C and the powder-blue mineral rich waters have many beneficial properties. However, recently there have been a number of changes that you should be made aware of.
The Blue Lagoon now promotes itself very heavily as an upmarket health spa. As the number of tourists visiting Iceland has greatly increased over the past few years, the Blue Lagoon has now found itself in a somewhat enviable position of being selective about the guests it wishes to encourage. For instance, they now advise that whilst school groups will be accepted, they are insisting that they adhere to a strict code of conduct which includes students refraining from making any undue noise or inconveniencing other visitors by splashing around in the water. At the same time they have increased the price of admission to students by over 100% in some cases, in recent years.
Furthermore, due to the growing number of tourists now visiting the Blue Lagoon, during busier periods some have found their Blue Lagoon experience to be overpriced, overcrowded and overrated. The entrance cost for groups is now £22 per person and so we suggest you consider this in relation to many other activities that you could include as an alternative to the Blue Lagoon, especially if you are working to a restricted budget.
For example, we could arrange a visit to several other well-appointed and very modern public swimming pools for just a couple of pounds per person, also heated with geothermal water and, within reason, no one will be adverse to students simply having a good time and letting off steam! Alternatively, you may wish to put the money towards one of our other optional activities which also represent great value for money such as a glacier walk, lava tube caving or extending your trip to include a visit to Skaftafell National Park and Jokulsarlon (the famous iceberg lagoon – a real highlight that many school groups miss). You might also like to consider the Nature Baths in Myvatn, North Iceland. From only £12 per person this offers all the benefits of the Blue Lagoon (including blue warm waters), but without the crowds and at around half the price; just one of many great reasons to get off the beaten track and explore other parts of Iceland!
Ultimately the choice is yours and it falls down to what you and your students want from your Iceland trip. The Blue Lagoon can still offer a very relaxing and worthwhile experience, particularly for first time visitors. Therefore, if your time and budget allows and you are travelling outside of peak periods we recommend it. However, if your reason for travelling to Iceland is to experience many of the natural geological wonders (of which the man-made Blue Lagoon is not), plus your time and budget is limited, we instead recommend a visit to one of the many other countless attractions which Iceland has to offer.