Puteoli was not buried by the eruption of Mount Vesuvius in 79 AD, like Pompeii and Herculaneum, but the city is in an area with much volcanic activity. The area to the north-east of modern Pozzuoli is known as the Campi Flegrei, the "Burning Fields". A famous feature of the area is the Solfatara crater, where people can walk around, but which continuously emits jets of steam with sulfurous fumes.

Click on the image to enlarge.
Map of the Bay of Naples by Karl Julius Beloch, 1879. Image: pompeiiinpictures.com.

The author with his daughter in the Solfatara crater. Photo: Jolande Videler.

The promontory of Pozzuoli, with the historic quarter called Rione Terra, and the surrounding area, known as La Starza, have been plagued by volcanic activity for millennia: earthquakes, seaquakes and a phenomenon called bradyseism. The name of the latter activity is derived from the Greek words bradus, "slow" and seismos, "earthquake". It is the gradual uplift or descent of an area, of several meters, caused by the filling or emptying of an underground magma chamber. Also quite recently, in the 1970's and 1980's, the city has suffered from upward bradyseism and earthquakes. During the restoration work many archaeological discoveries were made.

'Flight from trembling Pozzuoli'.
The newspaper Il Mattino reports on the earthquake of September 4, 1983.

Due to the rising and sinking of the area, the ancient coastline has shifted considerably. Underwater archaeologists have investigated remains on the bottom of the sea. Particularly famous is the sensational Parco sommerso di Baia, a bit further to the west.

Map showing changes of the coastline around the Pozzuoli promontory.
Image: Aucelli et al. 2018, fig. 1.