A number of years ago, a researcher with Columbia University’s Lamont-Doherty Earth Observatory spied some extremely large boulders in a place where they should not be found.

According to a report on natureworldnews.com, Ricardo Ramalho noticed boulders some 2,000 feet inland and at about 650 feet above sea level, and thinking the were out of place, lying on volcanic ground, and began to investigate.

Ramalho and his team considered several possibilities as to how the boulders arrived at their current location, but finally the most likely possibility was that the boulders had been thrown from an area around the Cape Verde island’s shoreline, since boulders of that composition were noted to be in that area.

But what type of event could move such massive rocks that far inland? The researchers concluded that a wave of at least 800 feet high would be required to lift the boulders high enough to place them where they are now.

Upon examining all the surrounding evidence, they surmised that a volcano located on the spot where the Fogo volcano is now, must have collapsed and sent a towering tsunami thundering across the Atlantic Ocean and over the area of the Cape Verde Islands, where some 250,000 people are living in the present.

Today, the Fogo volcano reaches around 9,300 feet above sea level, and is one of the most active volcanoes in the world, erupting about every 20 years and most recently last fall. These facts are leaving experts guessing if such a disaster may be in the works again.

The collapse that created the tsunami that re-located the boulders probably occurred some 73,000 years ago, estimate the researchers.

One of the more interesting aspects of the study is that it has revived the controversy over whether such an event is likely in the future, and should we be concerned that it could happen right away.

Ramalho, in a statement released, said, “Our point is that flank collapses can happen extremely fast and catastrophically, and therefore are capable of triggering giant tsunamis. They probably don’t happen very often. But we need to take this into account when we think about the hazard potential of these kinds of volcanic features.”