Campi Flegrei, like Yellowstone, is a volcano without a visible cone. While near Mt. Vesuvius, it may or may-not share lava connections to it. That entire area of Italy has multiple inactive volcanos with a worrisome potential due to the African tectonic plate moving north.
Should a typical super-volcano fissure eruption occur there, you would have multiple lines of erupting fissures making Naples and that area near uninhabitable. Lots of things to be concerned about if this danger comes to pass.
It sounds like Campi Flegrei is the site of an old very large eruption, like the Valley of 10,000 Smokes left after Katmie erupted in 1911 or 12. Anyone have more information/history on CF?
And we should never underestimate the potential for volcanic disaster. In 1902 politicians insisted that Mt. Pelee was not that dangerous so that people would stay in San Pierre for an important election. It was important that they stay so a white man, not a colored, be elected to the French national assembly. Then the mountain blew killing at least 30,000 people. After several months of paying coloreds and blacks a small disaster payment for living away from home, the government cut off the payments forcing the people to move back home even though the visiting volcano experts said their was strong danger of another pyroclastic eruption. They were right and 2,000 more people died.
We have also witnessed Mount St. Helens recently, and other nearby volcanoes could cause even more fatal eruptions including major flooding as snow is heated. Anyone remember the 23,000 people killed by the eruption caused flood in South America a few decades ago? The Pacific northwest has a lot of volcano danger areas.