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Ethiopia witnesses rare earth split
Addis Ababa, Dec 27 (DPA) A continental rifting process that normally takes
millions of years to form has developed over a span of seven weeks in the
Afar region of Ethiopia. It was a close study, using radar interferometry,
of an earth rupture developing into a rare axial rift zone -- a possible
future ocean basin.
Scientists from Ethiopia and Britain made four expeditions to the Da'ure
locality in the Afar Depression between mid-September and early October to
collect geophysical and geological data, said Atalay Ayele of the
Geophysical Observatory of the Addis Ababa University (AAU). It started with
a series of quakes that were first recorded Sep 14 in Da'ure, an area in the
lowlands of western Ethiopia that stretches from the central part of the
country to the Dahlak Islands of Eritrea in the Red Sea.
The volcanic activity, recorded at N 12.651 degrees longitude and E 40.519
degrees latitude, spewed ash for three continuous days and eventually
numerous cracks appeared on the ground, spreading fear among the pastoral
inhabitants. Unsettled by the phenomena of rumbling tremors, they approached
the regional authorities to ask the federal government in Addis Ababa to
look into it. The government asked experts in the field at the AAU to
investigate the phenomena, and if need be ask for assistance from
universities abroad, which is where the British scientist got involved.
"We were thus involved in a collaborative undertaking with earth scientists
from Britain to undertake further study to collect data in and around the
Da'ure locality," said Atalay. An image of the locality taken by a NASA
satellite orbiting the earth showed that an area of 60 km had developed an
eight-metre opening. "This was a fast opening rate within a span of about
two months, from Sep 14 to early November, an exciting event in scientific
terms," said Atalay.
"Compare this to the very slow movement of the plate tectonic affecting the
crust of the earth in the Afar region, which is about 17 mm per year," he
explained. Cindy Binger of Royal Holloway, University of London, presented
the findings at the fall meeting of the American Geophysical Union in San
Francisco. Atalay said there were no immediate concerns about the Afar
region, noting that it would take a couple of million years before the area
turns into an ocean basin.
For scientists researching the phenomena, the Afar region is a natural
laboratory where the transition between oceanic rift and continental rift is
visible on land. Such transition is also evident in Iceland. "The events we
witnessed in Afar for about seven weeks have enabled us to look into the
possible, faster rate of rifting in the region," said Atalay. "What we saw
was a microcosm of a process of an earth split that takes millions of years
to evolve into an ocean basin," he declared.
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