An 800-Foot Ancient Tsunami Once Heaved Truck-Sized Boulders Onto a High Plateau

Geologists have concluded that 73,000 years ago, a tsunami six times taller than the wave that hit Japan in 2011 struck off the coast of West Africa, in the Cape Verde islands. 

The tsunami was so powerful that it hurled elephant- and truck-sized boulders more than 600 feet uphill and onto a island plateau.

ancient-tsunami_1024x576.jpg
A giant tsunami six times taller than the wave that hit Japan in 2011 probably struck 73,000 years ago off the coast of West Africa.

Scientists had discovered these basalt and limestone rocks a few years ago—but, as is often the case in geology, they weren’t sure how they could’ve have ended up so far from their original formation place. All they knew was that 73,000 years ago, a massive chunk of an ancient volcano on the island of Fogo had collapsed and fallen into the sea. On the nearby Santiago Island, evidence of debris from an ensuing tsunami suggests that the event had wide-reaching geologic effects. But until now, researchers didn’t know how big the tsunami was, nor how many of them occurred.

The giant boulders, though, provide a missing link. The team, comprised of researchers from Columbia University’s Lamont-Doherty Earth Observatory, concluded that the 49 boulders (weighing up to 700 tons) they studied could only have been lifted to their current position by a colossal tsunami. The researchers report their geologic interpretation in the journal Science Advances.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s