But – and this is the key piece of information – the history of the volcano suggests that when this eruption does occur, it won’t destroy Rome after all.
Just under 610,000 years ago, a caldera (“cauldron”) was formed in the area when a huge rupture in a sizeable magma chamber forced its contents rapidly and violently out onto the surface, and the overlying rock cap sank down into the earth.
Between then and 351,000 years ago, it produced 280 cubic kilometers (67 cubic miles) of volcanic matter – more than enough to smother any major city. After this more explosive period, it became somewhat calmer, producing prolonged lava flows and launching the occasional gas-fueled slug of lava out of the primary vent, much like the famous Mount Etna does today.
After this phase, its most geologically recent activity has been to produce small pit craters called “maars” that form when water and magma mix beneath the ground. This style of eruption is known as phreatomagmatic, and is thought to only occur when water is trapped within the magma before expanding rapidly and explosively.
This means that the eruption intensity has been in decline for over half a million years, and unless something major changes beneath the site, it’s likely any subsequent eruption, although newsworthy, probably won’t eradicate the Italian capital.
Phew. No doom for Rome. rweisswald/Shutterstock