Continents on the move

Scientists have uncovered proof that the African continent is shifting apart.

According to the team led by the University of Leeds, Africa is being torn apart as Ethiopia’s rift valley slowly grows wider.
 
The 28-strong team are now taking this opportunity to track the progress of the continents on the move.
 
With a £2.5 million grant from the Natural Environment Research Council (NERC), the team plan to study the seismic events taking place in the remote Afar desert of Northern Ethiopia. It's here that two mighty shelves of continental crust, the African and Arabian plates, meet – and are tearing the landscape apart.
 
The shift happens at the same rate as human fingernails grow – about 16mm a year. However, the gradual build-up of underground pressure can lead to occasional bursts of cataclysmic activity.
 
The most dramatic event came in September 2005, when hundreds of deep crevices appeared within a few weeks, and parts of the ground shifted eight metres, almost overnight. More than two billion cubic metres of rising molten rock – magma – had seeped into a crack between the African and Arabian tectonic plates, forcing them further apart.
 
It has given Dr Tim Wright's team a unique opportunity to witness plate tectonics – the science of how continents are formed and move – at first hand. He said: "Much of the activity between the continental shelves takes place deep underwater at the mid-ocean ridges. Ethiopia is the only place on the planet where we can see a continent splitting apart on dry land."

Earthquake technology

Dr Wright and his colleagues will use satellite radar imaging to measure how the ground deforms. "In its simplest form, you are taking two snapshots of the same place, separated by a period of time, to see how far they have moved apart."
 
His team, which includes experts from Oxford, Cambridge, Bristol and Edinburgh universities, as well as international researchers from the US, New Zealand, France and Ethiopia, will also use GPS, seismometers, and other geophysical and geochemical techniques to determine the properties of rock and magma below the surface, and to monitor the crust's movement.
 
They will use the data to create a 3D computer model of how magma moves through the Earth's crust to make and break continents.
 
As the sides of the Ethiopian rift move apart, the gap between them is being plugged with molten rock which then cools to form new land, and in around one million year's time, the Red Sea could come flooding into the sinking region, re-shaping the map of Africa forever.
 
"It's very exciting because we're witnessing the birth of a new ocean," said Dr Wright.
 
"In geological terms, a million years is the blink of an eye. We don't precisely know what is going to happen, but we believe that it may turn parts of Northern Ethiopia and Eritrea into an island, before a much larger land mass – the horn of Africa – breaks off from the continent."

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