From: Berhane Habtemariam (Berhane.Habtemariam@gmx.de)
Date: Tue Nov 03 2009 - 07:00:40 EST
Giant Crack in Africa Will Create a New Ocean
By <http://www.livescience.com/php/contactus/author.php?r=editorial>
LiveScience Staff
posted: 03 November 2009 05:23 pm ET
A 35-mile rift in the desert of Ethiopia will likely become a new ocean
eventually, researchers now confirm.
The crack, 20 feet wide in spots, opened in 2005 and some geologists
believed then that it would spawn a new ocean. But that view was
controversial, and the rift had not been well studied.
A new study involving an international team of scientists and reported in
the journal Geophysical Research Letters finds the processes creating the
rift are nearly identical to what goes on at the bottom of oceans, further
indication a sea is in the region's future.
The same rift activity is slowly
<http://www.livescience.com/forcesofnature/060719_red_sea.html> parting the
Red Sea, too.
Using newly gathered seismic data from 2005, researchers reconstructed the
event to show the rift tore open along its entire 35-mile length in just
days. Dabbahu, a volcano at the northern end of the rift, erupted first,
then magma pushed up through the middle of the rift area and began
"unzipping" the rift in both directions, the researchers explained in a
statement today.
"We know that seafloor ridges are created by a similar intrusion of magma
into a rift, but we never knew that a huge length of the ridge could break
open at once like this," said Cindy Ebinger, professor of earth and
environmental sciences at the University of Rochester and co-author of the
study.
The result shows that highly active volcanic boundaries along the edges of
tectonic ocean plates may suddenly break apart in large sections, instead of
in bits, as the leading theory held. And such sudden large-scale events on
land pose a much more
<http://www.livescience.com/environment/top10_naturaldisasterthreats_us.html
> serious hazard to populations living near the rift than would several
smaller events, Ebinger said.
"The whole point of this study is to learn whether what is happening in
Ethiopia is like what is happening at the bottom of the ocean where it's
almost impossible for us to go," says Ebinger. "We knew that if we could
establish that, then Ethiopia would essentially be a unique and superb
ocean-ridge laboratory for us. Because of the unprecedented cross-border
collaboration behind this research, we now know that the answer is yes, it
is analogous."
The African and Arabian plates meet in the remote Afar desert of Northern
Ethiopia and have been
<http://www.livescience.com/environment/070130_africa_torn.html> spreading
apart in a rifting process - at a speed of less than 1 inch per year - for
the past 30 million years. This rifting formed the 186-mile Afar depression
and the <http://www.livescience.com/forcesofnature/060719_red_sea.html> Red
Sea. The thinking is that the Red Sea will eventually pour into the new sea
in a million years or so. The new ocean would connect to the Red Sea and the
Gulf of Aden, an arm of the Arabian Sea between Yemen on the Arabian
Peninsula and Somalia in eastern Africa.
Atalay Ayele, professor at the Addis Ababa University in Ethiopia, led the
investigation, gathering seismic data with help from neighboring Eritrea and
Ghebrebrhan Ogubazghi, professor at the Eritrea Institute of Technology, and
from Yemen with the help of Jamal Sholan of the National Yemen Seismological
Observatory Center.
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