This is CBS. I'm the world. I'm John Bachelors.

Tonga, an archipelago with major and minor islands in the Pacific until an explosion that is an underwater volcano.

Right now what we know is the rescue attempts are underway for those who have not been heard of

because the underwater cable was sliced at least in one, perhaps two places.

We also have incomplete reporting about the scale of this explosion.

And the best way to understand it is not the metrics that are underway to be measured, but also past events.

In that attempt I welcome Charles Pellegrino, my colleague of many years, the author of The Ghosts of Vesuvius,

which is a story about another enormous explosion that is burned into our historical memory.

This is the one that took place in the depths of the Roman Empire and destroyed several seaside resorts

leaving behind a record of life in the first century AD.

It also connects to another story that Charlie and his colleagues have explored, which is the story of Atlantis,

not at the gates of Hercules, but in an island now called Santorini in the Aegean that is also known as Tyra.

Charlie, a very good evening to you. The Tonga explosion connects to your learning, the Vesuvius explosion and the Tyra explosion.

Did you see anything irregular here? Some new twist of what a volcano can do to planet Earth. Good evening, Charlie.

This was an unusual explosion because it probably involved a lot of steam, basically seawater getting into the chamber,

and it turned out to be a very fast explosion, and by explosion, fast, I mean, of volcanic explosion usually takes place over many seconds.

This was a very rapid burst, sort of like when the asteroid hit the atmosphere in 1908 and an explosion that was about the same force,

10 to 15 megatons over Siberia, and this too was a very rapid explosion.

You saw shock rings radiating out from the explosion center, and we had satellites and we had the space station,

and from space we were watching this huge explosion in the Pacific.

You gave me the image which I enjoy very much remembering of the shock waves sweeping across the planet,

the surface of the planet, and colliding one from the east, one from the west over the Atlantic,

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