Volcanic Hazard Case Study: Eruption Of Eyjafjallajökull, Iceland, 2010 Flashcards
What caused the eruption?
- Iceland lies on the mid-Atlantic ridge, a constructive plate margin
- as the plates move apart due to movement of convection currents in Earth’s asthenosphere, magma rises to the surface to form several active volcanoes
E15 is located
Beneath an ice cap in Southern Iceland
The hazard risk for humans along the mid-Atlantic ridge is low because the activity mostly takes place
Underwater, but ne exception to this is the Island of Iceland
Iceland is populated, yet most of the 300,000+ people living there feel feel they are at relatively low risk from volcanic hazards because
Volcanic eruptions along this type of plate boundary are, in general, not highly explosive unlike those associated with destructive plate boundaries. However, E15 has nonetheless proved to be a major geo-physical hazard due to the the release of a very large ash and gas cloud in 2010
The volcanic eruptions starting in March, 2010 are considered to be a single eruption divided into different phases:
1- initially,a fissure opened up about 150m in length with 10-12 erupting lava craters ejecting lava which was basalt and relatively viscous causing lava stream to be slow
2- on 14th April, 2010, the eruption entered an explosive phase and ejected fine, glass-rich ash to 8km into the atmosphere which was then deflected to the east by westerly winds
- the second phase is estimated to have been a VEI 4 eruption which is relatively large but not nearly the most powerful eruption in VEI terms
Give some local primary primary effects:
- thick layer of ash fell on surrounding farm pastures, making pasture land wet and compact,making it very difficult to continue farming, harvesting or grazing livestock
- some local gravel roads blocked by falling ash
Give some example of local negative secondary effects:
- one of the most damaging secondary effects=as locally rivers rose as part of the ice cap melted disrupting roads and damaged buildings
- mudslides (lahars)- ash mixed with meltwater- the mudslides falling into the river raised channel beds increasing the flood risk also
Give some examples of international negative impacts?
- over a period of 8 days, 100,000 flights were cancelled accounting for almost 50% of total air traffic- British Airways had an approximate loss of £15-20 million per day. Earth’s westerly upper air circulation meant large areas of Europe were adversely affected by the dust cloud
- industries were affected by lack of imported raw materials e.g. Honda announced a partial halt to their production
- fresh food could not be imported, affecting supermarkets and producers globally
The disaster potential of this event was much higher than it would have been in the past due to
Widespread and routine use of jet aeroplanes, which has greatly increased global society’s vulnerability- fine ash entering the atmosphere would not impact on lives, other than the fact aeroplanes transverse this region
What were some benefits of the eruption (positive secondary effects)?
- nutrients released from ash may improve soil fertility
- reduction of travel over Europe meant over 2 million tonnes of carbon dioxide not released into atmosphere
- Eyjafjallajökull has become Icelandic tourist attraction with its own visitor centre; Icelandic tourist Board encourages people to visit the ‘land of ice and fire’ bringing benefits to local people and industries
State some responses?
- first response was that 800 locals were evacuated overnight (500 of which were farmers) and some roads were closed for fear of flash floods
- some UK citizens sailed their own boats across the English Channel to help pick up stranded tourists- in a manner reminiscent of the famous Dunkirk evacuation during WWII
- insurance industry had an important role helping people and businesses to cope with their financial losses
