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Probing plate tectonics

IT IS hardly a seismic event, but the study of plate tectonics has received a significant push forward. An international team of scientists studying recent seismic events in Northern Ethiopia is now in the process of plotting the progress of continental drift.

The 28-member team, led by a University of Leeds geophysicist, is focusing on the area where the African and Arabian tectonic plates meet. Clearly, the site is significant to the study. 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 it is possible to see a continent splitting apart on dry land.

The study of plates and their relationships to one another is central to our understanding of earthquakes, volcanoes, tsunamis and landform development. At a wider level, it has influenced virtually every discipline of the Earth sciences since the late 1960s and early 1970s, serving as a unifying model for explaining geologic phenomena that were hitherto considered unrelated.

For the current group of researchers, the most dramatic event occurred in September 2005, when hundreds of deep crevices appeared within a few weeks in Ethiopia’s Afar desert, and parts of the ground shifted some eight metres. More than two billion cubic metres of rising molten rock had seeped into a crack between the African and Arabian tectonic plates, forcing them further apart.

The team, which includes experts from Oxford, Cambridge, Bristol and Edinburgh universities, as well as scientists from the United States, New Zealand, France and Ethiopia, plans to monitor the movement of these plates to, among other things, determine the properties of rock and magma below the surface. By creating a computer model, they expect to simulate how magma moves through the Earth’s crust to make and break continents.

In around one million year’s time, according to current projections, the Red Sea could come flooding into the sinking region, reshaping the map of Africa forever. To consider the impact of the process in the larger scheme of things, it would be useful to remember —in the words of the team leader —that a million years is the blink of an eye in geological terms.