The Volcanic Eruptions of Italy was an event that occured during the 2012 apocalypse.
Presumably throughout the day of the 21st of December 2012, volcanoes in Italy erupted due to the Earth's crust becoming unstable and lava forcing its way to the surface, due to the Earth's core's temperature heating up so high. The volcanoes in Italy caused major damage to many areas of the country, destroying nearby cities. Some volcanoes located in the Tirrenian Sea, like Mount Stromboli, erupted and presumably generated massive waves that hit the majority of the west coast of the country, damaging all cities within the coast (Like Palermo, Naples, Rome, Pisa and Genoa). Lava and volcanic ash engulfed a vast portion of the peninsula, rendering it uninhabitable.
The remains of Italy were then swept by a megatsunami when the Worldwide Flooding occured, submerging it underwater.