Signs of the active volcano
The area around Vesuvius received its first warning sign that the mountain was reawakening when a 7.5 earthquake struck on the 5th of February. Of course the scientists back then didnt have the technology to realize that this was happening.
When did it erupt?
August 24, 79 A.D. in the afternoon
How did the city react?
Most of the people tried running after the first eruption but did not make it in time of course. Remember this the lava did not cause the deaths of the citizens nor did the ashes! There where 3eruptions and the 3rd one let out noxious gas that was several hundred degrees, when they breathed in the air they died almost instantly. Later did the ash fall on them that made there "casts".