The World's Next Ocean

Summary

In 2005, an earthquake in Ethiopia opened a gigantic crack, revealing that eastern Africa is undergoing rifting, a process where tectonic plates pull apart to create a new ocean. This phenomenon, which usually occurs at the bottom of the ocean, offers geologists a rare opportunity to study the formation of seafloor ridges and continental plate movement up close.

Highlights

A Giant Crack in the Earth00:00:03

On September 14, 2005, an earthquake in Afar, Ethiopia, was followed by numerous smaller quakes. On September 26, the Dabbahu volcano erupted, creating a 60-kilometer-long and up to eight-meter-wide crack in only ten days. This event, while not causing significant harm, captured the attention of geologists worldwide.

Africa's Ongoing Rifting00:00:45

The crack was a symptom of an ongoing seismic shake-up in Africa, where tectonic plates are pulling apart in a process called rifting. A magma plume from deep within the mantle is forcing the African and Arabian plates apart, forming the Great Rift Valley, which stretches over 3000 kilometers.

Studying the Great Rift Valley00:01:18

Scientists have studied the Great Rift Valley since the early 20th century. It is a system of fractures with significant seismic activity, including earthquakes and volcanic eruptions, caused by rising magma. A 2018 study used seismic networks in Ethiopia and Eritrea, recording almost 5,000 earthquakes in two years, and the region has also seen numerous volcanic eruptions.

A Rare Opportunity for Geologists00:02:05

While rifting is common at the ocean floor, the activity in Africa allows geologists to study the process directly. The 2005 event, where a large section of the rift cracked open all at once, was unexpected, as scientists previously believed such cracks opened incrementally.

The Birth of a New Ocean00:02:37

Eventually, the Horn of Africa will split from the continental plate, and as many parts of the Great Rift Valley are below sea level, seawater will flood in, creating a new ocean and turning the Horn of Africa into an island. This process has been ongoing for about 30 million years, widening at a rate of a couple of centimeters annually, meaning it will be tens of millions of years before the new ocean fully forms.