CASE STUDIES

The Restless Earth – Tohoku Earthquake, Japan and Eyjafjallajökull, Iceland

The Restless Earth – Tohoku Earthquake, Japan and Eyjafjallajökull, Iceland

Japan’s Tohoku earthquake (2011)

On Friday 11 March 2011, the Pacific Plate was pushed down beneath the edge of the Honshu Plate, causing the seabed to rise by several metres along hundreds of kilometres of the ocean floor. This gigantic release of energy pushed water upwards at great speed and with enormous force.

A tsunami cannot usually be seen when in deep ocean, but when it reaches the coast water is forced upwards to create a giant wave. The Tohoku Tsunami inundated a long stretch of Japan’s northern coast, killing thousands of people and obliterating entire towns and villages. At one point the wave is believed to have reached a height of almost 40 metres (131 feet).

Japan has experienced many tsunamis before, and tsunami walls were in place in many of the towns affected, but the size of the wave caught many by surprise. It is estimated that up to 20,000 people died as a direct result of the earthquake, mostly due to the tsunami.

Tsunamis are impossible to prevent, but can often be predicted; most damage is done when an earthquake takes place close to land and close to the surface of the seabed, when there is little time to circulate warnings. The Tohoku earthquake occurred just a few miles offshore, giving little opportunity for people to flee before the wave came.

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Eyjafjallajkull

When the Eyjafjallajkull (pronounced ‘EY-yah-fyah-lah-YOH-kuul’) volcano in Iceland erupted in spring 2010, huge quantities of ash were blasted for tens of kilometres into the atmosphere. Air traffic was

disrupted for months because of fears that jet engines might suck in dust, causing them to fail. When the ash fell to earth it also had a serious impact on farming in that area.

Like many volcanoes, there were several phases to the Eyjafjallajkull eruption. The volcano lies along the mid-Atlantic Ridge, which is a major fault line between the Eurasian and North American plates. The volcano is directly beneath the ‘jet stream’, which flows across the UK and mainland Europe, which meant ash was distributed across the continent. Although the Eyjafjallajkull eruption is now over, some scientists believe another eruption is possible, either here or at one of the other volcanoes in the area.