Here's why:

* Eruptions: Vesuvius has a history of significant eruptions, most famously the one that buried Pompeii and Herculaneum in 79 AD. It has also erupted in more recent times, most recently in 1944.

* Seismic Activity: The volcano shows signs of ongoing activity, including regular tremors and gas emissions.

* Monitoring: Vesuvius is closely monitored by volcanologists who track its activity to anticipate and prepare for future eruptions.

While the volcano may be quiet at times, its history and current activity indicate that it is not dormant or extinct.