This radar image highlights portions of three of the lakes located in the Western Rift of the Great Rift Valley, a geological fault system of Southwest Asia and East Africa: Lake Edward (top), Lake Kivu (middle) and Lake Tanganyika (bottom).
Arrays of sensors stretching across more than 1,500 miles in Africa are now probing the giant crack in the Earth located there — a fissure linked with human evolution — to discover why and how continents get ripped apart.
Over the course of millions of years, Earth's continents break up as they are slowly torn apart by the planet's tectonic forces. All the ocean basins on the Earth started as continental rifts, such as the Rio Grande rift in North America and Asia's Baikal rift in Siberia.
The giant rift in Eastern Africa was born when Arabia and Africa began pulling away from each other about 26 million to 29 million years ago. Although this rift has grown less than 1 inch (2.54 centimeters) per year, the dramatic results include the formation andongoing spread of the Red Sea, as well as the East African Rift Valley, the landscape that might have been home to the first humans.
"Yet, in spite of numerous geophysical and geological studies, we still do not know much about the processes that tear open continents and form continental rifts," said researcher Stephen Gao, a seismologist at the Missouri University of Science and Technology in Rolla, Mo. This is partly because such research has mostly focused on mature segments of these chasms, as opposed to ones that are still in development, he explained. ...more