Naples Life,Death & Miracle

Big Archie & Living on the Edge

The Archiflegrean Caldera is the area bounded
by the red lines with wedges. The area shown
in the map is about 30 kilometers across.

I have always known that the area is, volcanically, a bit “iffy.” After all, from my balcony (about where the word "Chiaia" is, above "Bay of Naples" in this image) I can see Mt. Vesuvius way over to the east. It (Vesuvius, not my balcony), has been quiet, lo, these last 66 years. (And that’s just one 6 short of a hell of a volcano!) But that’s only the tip of the volcano. Vesuvius is a child (less than 20,000 years old) compared to the roaring land-forming engines that earlier produced almost everything else in this image: the Fuorigrotta Plain and everything to the west of the Posillipo hill until you get to Capo Miseno, Monte di Procida, and Cuma at the western end of the Gulf of Naples. There are still remnants (Monte di Procida is one) of the cataclysmic caldera collapse of the so-called Archiflegrean volcano or Caldera (also known as the Campanian Ignimbrite Eruption); that is, bits of the ancient volcano rim of Big Archie exploded 40,000 years ago, tore the roof off itself and settled back to sea-level and below. As you go through the area, you go through Agnano, the Astroni, and other places, all parts of the Campi Flegrei, or Flegrean Fields. Flegrean means "fiery." They are remnant volcanoes from the so-called Second Flegrean Period (c. 20,000 ago), which featured the simply-named Flegrean Volcano (bounded by the black lines with wedges, centered on the town of Pozzuoli). One area, the Solfatara, is still wheezing if not active, but it could erupt, they say. The Flegrean Volcano produced the Posillipo hill, the slopes of which attracted the Greeks, then Romans and now a bunch of other optimists who have never studied geology.

(See this page for a photograph shot from the NE rim — the Camaldoli convent across the entire Campi Flegrei to the remnant SW rim above Baia.)

update added Nov. 2018 - See this link for the latest studies on the ominous "bulge beneath the bay."

A bit to the east, I (and thousands of others—photo, right) live on the northern slope of another earth-engine called the Chiaia volcano (again, right where that word, "Chiaia" is in the above image). It had not occurred to me before, but as I look from my balcony to the south, the postcard below me is a vast amphitheater, a semi-circle with the Egg Castle on the left and Mergellina on the right with that western end of the amphitheater extending out to a point called Cape Posillipo. The stage below me (photo, below) is at sea-level and Capri is dead ahead, a backdrop, 25 miles away. From the slopes of the ancient Chiaia crater, we all have great seats for whatever is to come. That original explosion was a piker compared to Big Archie of some eons earlier, but it did form what is now the Chiaia section of Naples and most of the Vomero hill above it.

From the sea, the Vomero hill above me seems to run over to the west and form a single long ridge with the Posillipo hill. That is deceptive. They do run together, after a fashion, but only because the Chiaia volcano came first, and then the smaller-than-Archie Flegrean volcano to the west blew and spat out the Posillipo hill partially on top of it.

All of this volcanic activity has made the area rich in yellow tuff, a sandstone, the ubiquitous building material in Naples. I am currently in the midst of translating a book about the subsoil of Naples. Co-translator, Larry Ray, writes this in his presentation of the translation for the Napoli Underground website:

...the tuff sandstone strata are honeycombed with hundreds and hundreds of gigantic manmade cavities where the durable sandstone had been quarried and brought to the surface to build palaces, villas and other buildings over the centuries. Additionally other voids included railroad tunnels, ancient Greek and Roman aqueducts and water reservoirs, long tunnels from the city's pneumatic mail and message network from the early 1900's, as well as elaborate network of ancient as well as operating sewer lines, gas lines and other similar cavities...

All of that is a cause for concern in construction around here. There is not an area in the city that is not undermined in some fashion or other. And maybe not even a building. We get earth slides and cave-ins frequently. I have learned to be as fatalistic about that as I am about volcanoes. My Chiaia explosion must have come from right where that rich guy’s yacht is anchored. If Chiaia goes “ka-blooey” (to use the geological term) again, he’s a goner. But, then, so am I.

science portal