In the years leading up to the eruption of Mount Versuvius, minor quakes and tremors were not uncommon throughout the region. Quakes occuring across the region effected neighbouring cities such as Herculaneum and Nuceria. But on the 5th of February, 62 AD a massive earthquake caused devestating damage around the Bay of Naples and parts of Pompeii. The writer, Pliny the Younger, wrote about the small but common tremors during the time before the large earthquake. It is beleived that the earthquake, in modern terms, would have been registered as a 5 or 6 on the Richter scale. Pompeii was not the only city affected by this devestating earthquake, nearby Herculaneum and Nuceria. In all three of these cities, temples, houses, roads and monuments were damaged. While some citizens of Campania relocated and migrated to other cities in the roman empire. Most citizens stayed and rebuilt what they had left. Theft and starvation were all throughout the cities and towns in the region affected by the monster eartquake. On the 24th of August 79 AD. Mount Versuvius erupted and destroyed nearly everything in its path. Tons of ash and pumice spilled down the mountainside and flooded the cities of Herculaneum and Pompeii. Pompeii was covered in 5 to 6 metres of ash.
Information taken from - http://en.wikipedia.org/wiki/Pompeii