Split earth in Ethiopia gives unusual glimpse at growing sea

Ever since since the Earth first started cooling billions of years ago, tectonic plates have been shifting and sliding around. These processes are usually very slow, and so while there have obviously been some dramatic changes since all land was clumped together in a single super-continent, in human memory, things may feel like they’ve settled, until they start shaking again in the form of an earthquake. Shakes and tremors don’t always make the long-term patterns clear, especially under rubble, rocks and water. A split in Ethiopia, on the other hand, is giving us an unusual look at tectonic movement that may seem calm now, but is expected to eventually open up a new ocean.

Eruptions and expansions

The crack originated from the Dabbahu volcano, and was first found in 2005. The actual splitting probably looked rather dramatic, as magma pushed it’s way underground, then up through a new opening in the surface. Rather than build up into new rock, the split was described as “unzipping” along the underlying fault line, and now reaches as far as 20 feet across at its widest points. This obviously isn’t the biggest hole in the ground, but the location and recorded seismic activity point to it being the start of a larger trend.

While you can’t see it all on the surface, this rift is actually 35 miles long. It’s also connected to similar widening in the earth underneath the Red Sea (yes, the Red Sea is parting itself.) This all seems to be part of the spreading of the African and Arabian tectonic plates, which have been moving apart at a rate of a bit less than 1 inch a year. Compared to that, this new crack is a bit of a jump in the growth rate, but overall this new Afar depression won’t connect and transform the Red Sea for around a million years.

Crunching, sliding or expanding

This might seem like a very unusual development based on the kinds of seismic activity that we usually see in the news. Much of that is due to very different movements around the Pacific Ocean, where tectonic plates are pushing into each other, or sliding and slipping along or under each other. Basically, the Pacific needs more breathing room. However, the Atlantic Ocean is actually home to something similar to this Ethiopian rift. In the center of the ocean lies the Mid-Atlantic Ridge, the seam where the Eurasian and North American Plates and the South American and African plates are growing and separating from each other. While there’s around a similar amount of growth per year, most of it doesn’t break any buildings so we’re less likely to notice.

Source: Giant Crack in Africa Will Create a New Ocean, Live Science