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 north-eastern Ethiopia.
It was a close study, using radar interferometry, of an earth rupture developing into a rare axial rift zone — a future possible ocean basin.
As Associate Professor Atalay Ayele of the Geophysical Observatory of the Addis Ababa University (AAU) tells it, 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.
The series of quakes was first recorded at the AAU on September 14 in Da’ure, an area in the lowlands of the Western Ethiopia Escarpment 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 in the ground, spreading fear among the pastoralist inhabitants.
Unsettled by the unusual 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 in the Afar region and, if necessary, ask for assistance from universities abroad, which is where the British scientist got involved.
”We were thus involved in 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 Da’ure locality taken by an Earth-orbiting Nasa satellite showed that an area of 60km had developed an 8m opening.
”This was a fast opening rate within a span of about two months, from September 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 17mm per year,” he explained.
Professor 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 the Afar region for about seven weeks, beginning in mid-September, have enabled us to look into the possible faster rate of rifting in the Afar 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. — Sapa-DPA