Eruption of Vesuvius (AD 79): How Pompeii Was Buried

The eruption of Mount Vesuvius in AD 79 was one of the most famous natural disasters of the ancient world. Over about two days, the volcano on the Bay of Naples in southern Italy buried the Roman towns of Pompeii and Herculaneum, along with villas and smaller settlements, under ash, pumice and searing volcanic flows. The towns lay hidden for more than 1,600 years, and their rediscovery has given historians an unrivalled picture of everyday Roman life.

Background: towns beneath a sleeping volcano

In the first century AD the Bay of Naples was a wealthy, busy region at the height of the Pax Romana. Pompeii was a market town with perhaps 10,000 to 12,000 inhabitants, though estimates vary. Herculaneum was smaller and more prosperous, and wealthy Romans built seaside villas along the coast at places such as Oplontis and Stabiae.

The people living there did not regard Vesuvius as a dangerous volcano. It had not erupted in living memory, and its slopes were covered with vineyards. The geographer Strabo had noted that its summit looked burnt, but few drew any conclusion from this. Warning signs were not understood: a powerful earthquake in AD 62 or 63 badly damaged Pompeii, and some buildings were still being repaired when the eruption came. Pliny the Younger later recalled that small tremors had been felt for several days before the eruption, but that they were not thought alarming because they were common in the region.

Rome itself had a new emperor. Titus had succeeded his father Vespasian only in June AD 79, and the disaster was one of the first crises of his short reign.

What happened during the eruption

The eruption began around midday or early afternoon, when a huge column of gas, ash and pumice shot into the sky. Modern volcanologists estimate that it rose roughly 30 kilometres high. Winds carried the debris south-east, and pumice and ash fell on Pompeii for many hours, piling up on roofs until many collapsed.

Herculaneum, to the west of the volcano, received little ash at first. During the night and the following morning, however, the eruption column partly collapsed. This sent pyroclastic surges and flows, fast-moving avalanches of hot gas and volcanic material, down the mountain’s slopes. They reached Herculaneum first and later swept into Pompeii, killing everyone who remained. Studies of the victims suggest temperatures of several hundred degrees Celsius, enough to kill almost instantly.

This type of eruption, with a tall column followed by deadly flows, is now called a “Plinian” eruption, after the writer who described it. The same pattern has been seen in modern eruptions such as that of Mount St. Helens in 1980.

Pliny’s eyewitness account

The only surviving eyewitness account comes from Pliny the Younger, who was about 17 years old at the time. He was staying at Misenum, across the bay, with his uncle Pliny the Elder, a famous scholar, author of the encyclopedic Natural History, and commander of the Roman fleet stationed there.

Some 25 years later, the historian Tacitus asked Pliny the Younger how his uncle had died, and Pliny replied in two letters. He described the cloud rising above the mountain in the shape of an umbrella pine tree. His uncle first planned to sail closer out of scientific curiosity, then received an appeal for help from a woman named Rectina whose villa lay at the foot of the mountain, and turned the expedition into a rescue mission with the fleet’s warships.

Unable to land near the volcano, Pliny the Elder went to Stabiae, where he stayed with his friend Pomponianus. He died on the shore there the next day, apparently overcome by fumes or by a medical condition. Pliny’s second letter describes his own escape with his mother amid darkness, earth tremors and panic, as crowds fled Misenum along the roads.

The victims

Many residents probably fled during the first hours of ashfall, but thousands did not or could not. At Pompeii, the remains of around 1,150 people have been recovered so far, and about a third of the town has yet to be excavated. Total death tolls for the region are uncertain and are generally estimated in the low thousands.

At Herculaneum, excavations from 1980 onwards uncovered the skeletons of more than 300 people who had sheltered in boat houses on the shore. They are an important source of information about the health, diet and injuries of ordinary Romans.

The Roman historian Suetonius records that Titus appointed senators to organise relief in Campania and used the property of victims who died without heirs to help rebuild the affected towns. Pompeii and Herculaneum themselves were never reoccupied.

Dating the eruption

For centuries the eruption was dated to 24 August, the date given in the best-known manuscripts of Pliny’s letter. Other manuscripts give different readings, however, and archaeologists noticed evidence that seemed to point to autumn: remains of pomegranates and other autumn fruit, braziers in use, heavier clothing on some victims and wine apparently sealed in jars after the harvest.

In 2018 excavators at Pompeii found a charcoal inscription in a house under renovation, dated to the sixteenth day before the Kalends of November, which corresponds to 17 October. Because charcoal writing fades quickly, many scholars now believe the eruption took place after that date, most often suggested as 24 October AD 79. The question is not fully settled, and some historians still defend the traditional date.

Rediscovery and excavation

Herculaneum was found by well-diggers in the early 18th century, and official excavations began there in 1738. Digging at Pompeii started in 1748, and an inscription found in 1763 confirmed the site’s identity. Early excavations were often treasure hunts, carried out for the Bourbon kings of Naples, who removed statues, wall paintings and other finds to their palaces and museums. Methods gradually became more scientific, and the discoveries helped inspire the neoclassical style in European art and architecture.

In 1863 the archaeologist Giuseppe Fiorelli began pouring plaster into the hollows left in the hardened ash by decayed bodies. The resulting casts show victims in their final positions and remain some of the most moving objects from the ancient world. Pompeii, Herculaneum and Torre Annunziata were listed together as a UNESCO World Heritage Site in 1997.

At Herculaneum, the luxurious Villa of the Papyri yielded a library of carbonised papyrus scrolls in the 1750s, the only library to survive from the classical world. The scrolls are too fragile to unroll, but since 2023 researchers using high-resolution scans and machine learning have begun to read passages from them.

Timeline

• AD 62 or 63: A strong earthquake damages Pompeii and other towns around the Bay of Naples.
• AD 79, first day of the eruption (traditionally 24 August, possibly 24 October): A towering eruption column forms and pumice falls on Pompeii.
• AD 79, following night and morning: Pyroclastic surges and flows destroy Herculaneum and then Pompeii; Pliny the Elder dies at Stabiae.
• c. AD 106–107: Pliny the Younger writes his two letters about the eruption to Tacitus.
• 1738: Official excavations begin at Herculaneum.
• 1748: Excavations begin at Pompeii.
• 1863: Giuseppe Fiorelli introduces the technique of making plaster casts of victims.
• 1944: Vesuvius has its most recent eruption to date.

Legacy

The disaster that destroyed Pompeii and Herculaneum also preserved them. Streets, houses, shops, wall paintings, graffiti and household objects survived in a way that is almost unique, giving a detailed picture of Roman life in the first century AD. The sites remain among the most visited archaeological attractions in the world.

Vesuvius is still an active volcano, and some 600,000 to 700,000 people live in the official red zone around it. It is one of the most closely monitored volcanoes on Earth. Like the later eruption of Krakatoa in 1883, the events of AD 79 remain a reference point for understanding how violent eruptions affect people living nearby.

By the numbers

Myths and facts

Myth: Pompeii was destroyed by lava. No lava flows reached the towns. They were buried by pumice and ash and then struck by pyroclastic surges and flows.

Myth: the whole population died. The remains found so far suggest that most inhabitants escaped during the first hours of the eruption. The victims were those who stayed behind or could not get away.

Myth: the victims suffocated slowly in the ash. Some people did die from falling debris or ash, but research on the remains suggests that many were killed very quickly by the extreme heat of the pyroclastic surges.

Myth: the eruption came without warning. Earthquakes had shaken the region for years and tremors were felt in the days before, but the Romans did not recognise Vesuvius as a volcano that could erupt.

Why it matters

The eruption of Vesuvius turned a natural disaster into a time capsule. It gave the world its first detailed written description of a volcanic eruption, and its buried towns continue to shape what we know about the Roman world.