BY DAVID CHESTER and ANGUS DUNCAN

In 2005, The Geographical Journal published a paper by Professor Dave Chester (University of Liverpool) and Dr Martin Degg (University of Chester) on volcanic and seismic hazards in Peru. Here, Prof. Chester and Prof. Angus Duncan (University of Bedfordshire) reflect on the impact of the recent volcanic episode in Iceland.

At 10 pm, on Tuesday April 21, airports throughout the United Kingdom re-opened following an unprecedented five days during which 95,000 flights in Western Europe were cancelled. The reason given was the possible calamitous effects of a plume of ash produced by Eyjafjallajökull volcano in Iceland.

Erupting from beneath an icecap, ash was formed by the contact of magma (at over 1000⁰C) with water and ice. It was the interaction between the magma and water that gave rise to the explosivity generating large volumes of finely comminuted ash.

This eruption is quite different to that of the volcanic events that caused the famous examples of passenger jets losing engine power when the planes encountered the plumes of Galunggung, Java, 1982 and Redoubt, Alaska, 1989. In both these cases the eruptions were major explosive events which were relatively short lived and injected ash to high altitudes (Miller and Casadevall 2000).

Stranded Passengers

As a consequence of the Eyjafjallajökull eruption both in Europe and more distant destinations many thousands of travellers were stranded and the economic impact of the lack of aircraft movements was profound. Airlines lost a cumulative $US1.7 billion, while the cost of lost productivity in Europe may have been over $US 600 million per day. Around 221 tonnes of fresh food is normally flown to Britain every day and the impact on producers in Kenya and other distant locations was serious, forcing the waste of many tonnes of fruit and vegetables.

Photo by plasmastik

To many people in Britain the impact of the volcanic plume came as a shock, but in terms of historic Icelandic eruptions the effects of Eyjafjallajökull were mild. An  eruption in 1695 produced a sulphurous fog across Northern Scotland, while in 1783 a large lava eruption at Laki was associated with sulphur-rich clouds that covered Western Europe from the summer of 1783 until early 1784, producing in their wake high temperatures and poor air quality which took its toll on the elderly and those with respiratory problems. In fact there was particularly high mortality in regions of central England, for example in certain parishes in mid-Bedfordshire (Witham and Oppenheimer 2005, Grattan et al 2007). In 2010, the problem was not gas but fine ash, which can have a damaging effect on sensitive machinery such as aircraft engines and flight instruments, as well as causing abrasion to windscreens, bodywork and control surfaces.

Closing Airspace

British airspace was closed by the CAA (Civil Aviation Authority) on the basis of a pollution dispersal model produced by the UK Meteorological Office. Known as NAME (Nuclear Accident Model), it was developed following the 1986 Chernobyl accident. After five days and under pressure from airlines, some of whom had carried out test-flights, on the evening of April 21 it was decided to allow flights to resume from UK airports.

The no-fly zone was greatly reduced in area with the CAA stating that their decision was based on assurances from engine and aircraft manufacturers that safety would not be compromised if flights were routed through zones with some volcanic ash pollution. Arguments that the ‘no-fly policy’ had been far more restrictive than was strictly necessary in terms of the risk to aircraft will probably lead to compensation being sought from governments both in the UK and Western Europe.

Longer-term Consequences

The longer-term impact of the Eyjafjallajökull eruption on global and regional climate is likely to be minimal. To produce a significant global reduction in temperatures requires a sulphur-rich eruption, which reaches the stratosphere and occurs at or near to the tropics. Such an eruption occurred at Mount Pinatubo in the Philippines in June 1991 and caused the depression of global temperatures for several years. An even greater impact was produced by the 1815 eruption of Tambora in Indonesia which was responsible for 1816 being designated the ‘year without a summer’ in North America and Western Europe.

At the time of writing (late April 2010) the eruption appears to be on the wane, although the three previous eruptions of Eyjafjallajökull which are recorded in the historical record have been associated, not only with longer eruptions but also with the near simultaneous eruption of the much larger Katla volcano. But the incident did provide a timely reminder of how susceptible our highly networked societies - including just-in-time supply chains - can be to sudden environmental changes.

Online Resources

The progress of the eruption may be followed on the following websites:

The Nordic Volcanological Centre

The London Volcanic Ash Advisory Centre

The Icelandic Meteorological Office, which provides daily status reports on the activity of  Eyjafjallajökull

The response of the International Union of Geodesy and Geophysics to this eruption

References

Grattan J, Michnowicz S and Rabartin R 2007. The long shadow: understanding the influence of the Laki Fissure Eruption on human mortality in Europe in Grattan J and Torrence R eds Living under the shadow Left Coast Press, California 153-174.

Miller T P and Casadevall T J 2000 Volcanic ash and hazards to aviation in Sigurdsson H ed Encyclopedia of Volcanoes Academic Press, San Diego 913-930.

Witham C S and Oppenheimer C 2005 Mortality in England during the 1783-4 Laki Craters eruption  Bulletin of Volcanology 67 15-26

Degg M R and Chester D K (2005) Seismic and volcanic hazards in Peru: changing attitudes to disaster mitigation Geographical Journal Volume 171 Issue 2, Pages 125 - 145