[4][5] Archaeological excavations have revealed much of the towns and the lives of the inhabitants leading to the area becoming Vesuvius National Park and a UNESCO World Heritage Site.

[13] Suetonius recorded that the emperor continued singing through the earthquake until he had finished his song, while Tacitus wrote that the theater collapsed shortly after being evacuated.

The inhabitants of the area surrounding Mount Vesuvius had been accustomed to minor tremors in the region; Pliny the Younger wrote that they "were not particularly alarming because they are frequent in Campania".

[15][16] Pliny the Younger, author of the only surviving written testimony, described the morning before the eruption as normal; however, he was staying at Misenum 29 kilometres (18 mi) from the volcano across the Bay of Naples.

[17] Around 1:00 p.m., Mount Vesuvius erupted violently, spewing up a high-altitude column from which ash and pumice began to fall, blanketing the area.

[15] At some time in the night or early the next day, pyroclastic flows in the close vicinity of the volcano began; lights seen on the mountain were interpreted as fires, and people as far away as Misenum fled for their lives.

[15] Pliny the Younger wrote: broad flames shone out in several places from Mount Vesuvius, which the darkness of the night contributed to render still brighter and clearer...

[19]Sigurðsson, Cashdollar, and Sparks undertook a detailed stratigraphic study of ash layers based on excavations and surveys, published in 1982.

Concentrated to the south and southeast, two pyroclastic surges engulfed Pompeii with a 1.8-metre-deep (6 ft) layer, burning and asphyxiating any living beings who had remained behind.

Herculaneum, Pompeii, and Oplontis received the brunt of the surges and were buried in fine pyroclastic deposits, pulverized pumice and lava fragments up to 20 m (70 ft) deep.

The eruption is considered primarily phreatomagmatic, i.e. a blast driven by energy from escaping steam produced by seawater seeping into the deep-seated faults and interacting with hot magma.

In an article published in 2002, Sigurðsson and Casey concluded that an early explosion produced a column of ash and pumice which rained on Pompeii to the southeast but not on Herculaneum, which was upwind.

Pliny the Younger saw an extraordinarily dense cloud rising rapidly above the mountain:[36]the appearance of which I cannot give you a more exact description of than by likening it to that of a pine-tree, for it shot up to a great height in the form of a very tall trunk, which spread itself out at the top into a sort of branches.

[...] it appeared sometimes bright and sometimes dark and spotted, according as it was either more or less impregnated with earth and cinders.These events and a request by messenger for an evacuation by sea prompted the elder Pliny to order rescue operations in which he sailed away to participate.

His nephew attempted to resume a normal life, continuing to study and bathe, but that night a tremor woke him and his mother, prompting them to abandon the house for the courtyard.

As the ship was preparing to leave the area, a messenger came from his friend Rectina (wife of Bassus[38]) living on the coast near the foot of the volcano, explaining that her party could only get away by sea and asking for rescue.

[19] He set off across the bay but encountered thick showers of hot cinders, lumps of pumice, and pieces of rock in the shallows on the other side.

Advised by the helmsman to turn back, he stated "Fortune favors the brave" and ordered him to continue to Stabiae (about 4.5 km or 2.8 mi from Pompeii), where Pomponianus was.

[39] Very likely, he had collapsed and died, the most popular explanation for why his friends abandoned him, although Suetonius offers an alternative story of his ordering a slave to kill him to avoid the pain of incineration.

In the first letter to Tacitus, his nephew suggested that his death was due to the reaction of his weak lungs to a cloud of poisonous, sulphurous gas that wafted over the group.

[41] Apart from Pliny the Elder, the only casualties of the eruption to be known by name were the Herodian princess Drusilla and her son Agrippa, who was born in her marriage with the procurator Antonius Felix.

[46] The contorted postures of bodies as if frozen in suspended action were not the effects of long agony, but of the cadaveric spasm, a consequence of heat shock on corpses.

[49] Herculaneum, which was much closer to the crater, was saved from tephra falls by the wind direction but was buried under 23 metres (75 ft) of material deposited by pyroclastic surges.

"[50] Suetonius, a second-century historian, in his Life of Titus simply says that, "There were some dreadful disasters during his reign, such as the eruption of Mount Vesuvius in Campania.

"[51] Writing well over a century after the actual event, Roman historian Cassius Dio (as translated in the Loeb Classical Library 1925 edition) wrote that, "In Campania remarkable and frightful occurrences took place; for a great fire suddenly flared up at the very end of the summer.

This date came from a 1508 printed copy of a letter addressed by Pliny the Younger to the Roman historian Tacitus, originally written some 25 years after the event.

In 1797, the researcher Carlo Rosini reported that excavations at Pompeii and Herculaneum had uncovered traces of fruits and braziers indicative of autumn, not the summer.

More recently, in 1990 and 2001, archaeologists discovered more remnants of autumnal fruits (such as the pomegranate), the remains of victims of the eruption in heavy clothing, and large earthenware storage vessels laden with wine (at the time of their burial by Vesuvius).

[55] In 2007, a study of prevailing winds in Campania showed that the southeasterly debris pattern of the first-century eruption is quite consistent with an autumn event and inconsistent with an August date.

It was found in an area of a house that was in the process of being renovated, likely just before the volcano erupted",[57] while the charcoal writing itself is "fragile and unlikely to have been preserved for years prior to the utter destruction of Pompeii.