Knowing Vesuvius

BEN119473From the House of the Centenary IX.8.6

Two scholars from the University of Chicago have recently completed a new translation of the Tempest Stela, a 3,500 year-old Egyptian text from Thebes. This text describes days of weather consisting of the ‘sky being in storm without cessation’, a ‘tempest of rain’, and the dead floating down the Nile like boats of papyri. The conclusions from this new reading suggest this weather pattern is a result of the volcanic eruption at Thera, and actually gives a new date to the event, more in line with recent carbon dating than scholars have previously thought.

The recording of volcanic activity in the ancient world is something that is surprisingly overlooked by most who study Pompeii. There is a prevalent belief amongst Pompeian scholars that those who lived in the shadow of Vesuvius nearly two thousand years ago hadn’t the slightest clue it was a volcano. This is largely due to the fact that the last known event had taken place more than a thousand years before, and no written record of the Avellino eruption existed. Yet there is a large amount of evidence from around the ancient Mediterranean that suggests its inhabitants were all too familiar with volcanic landscapes, eruptions, and other kinds of seismic activity. From the sixth century BC, Greek natural philosophers were writing about volcanic events, both from the perspective of observation and mythological origin. Volcanoes were often identified as the result of Titans, the location of the forge of the fire-god Vulcan, or as the entrance to the underworld. The earliest theories on volcanoes and earthquakes focused on underground wind and fire, as is evident from the description found in Book 6 of Lucretius’ de rerum Natura:

‘And besides,
When subterranean winds, up-gathered there
In the hollow deeps, bulk forward from one spot,
And press with the big urge of mighty powers
Against the lofty grottos, then the earth
Bulks to that quarter whither push amain
The headlong winds.’

The idea of wind or trapped air causing seismic events can also be found in Seneca. Writing within a few years of the earthquake that struck Pompeii in AD 62, he explains some of the occurrences surrounding the quake as a result of ill air from beneath the ground:

Seneca Naturales quaestiones 27.-1-2

‘But some particular events are reported to have occurred in this Campanian earthquake, and they require explanation. They say that a flock of hundreds of sheep was killed in the Pompeii area. There is no reason for you to think this happened to those sheep because of fear: we have said that a plague commonly occurs after major earthquakes, and this is not surprising. For many causes of death are lurking deep below: the air itself can be unhealthy for those who breath it, either through a defect in the earth, or because the air is stagnating inertly in perpetual darkness, or because of contamination by the corrupting effects of subterranean fires.’

Regardless of how well ancient Romans understood the cause of earthquakes or volcanic activity, a number of authors, writing in the century before the great Plinian eruption of AD 79, described both Vesuvius and the region in a manner that illustrates a good awareness of the fiery past of the area, and the similarity to other areas that were currently seismically active. In a discussion on building materials, the first century BC architect Vitruvius extolls the unique properties of pozzolana, a volcanic sand that forms the basis of an extraordinary durable cement:

Vitruvius de Architectura II.6.1-3
‘It is found about Baiæ and the territory in the neighbourhood of Mount Vesuvius; if mixed with lime and rubble, it hardens as well under water as in ordinary buildings. This seems to arise from the hotness of the earth under these mountains, and the abundance of springs under their bases, which are heated either with sulphur, bitumen, or alum, and indicate very intense fire. The inward fire and heat of the flame which escapes and burns through the chinks, makes this earth light; the sand-stone (tophus), therefore, which is gathered in the neighbourhood, is dry and free from moisture…It is moreover said that in former times fires under Vesuvius existed in abundance, and thence evolved flames about the fields…The species of sponge-stone, however, thence obtained, is not found except in the neighbourhood of Ætna and the hills of Mysia.’

Vitruvius recognises that Vesuvius once was an active volcano, and even draws parallels between the characteristics of the Campanian mountain with the active Aetna on Sicily. Similarly, Strabo recognises that the land of Vesuvius and Aetna share the same ashy soil suitable for vines:

Strabo Geographica V.4.8
‘Above these places lies Mt. Vesuvius, which, save for its summit, has dwellings all round, on farm-lands that are absolutely beautiful. As for the summit, a considerable part of it is flat, but all of it is unfruitful, and looks ash-coloured, and it shows pore-like cavities in masses of rock that are soot-coloured on the surface, these masses of rock looking as though they had been eaten out by fire; and hence one might infer that in earlier times this district was on fire and had craters of fire, and then, because the fuel gave out, was quenched. Perhaps, too, this is the cause of the fruitfulness of the country all round the mountain; just as at Catana, it is said, that part of the country which had been covered with ash-dust from the hot ashes carried up into the air by the fire of Aetna made the land suited to the vine; for it contains the substance that fattens both the soil which is burnt out and that which produces the fruits; so then, when it acquired plenty of fat, it was suited to burning out, as is the case with all sulphur-like substances, and then when it had been evaporated and quenched and reduced to ash-dust, it passed into a state of fruitfulness.’

He actually takes this further, realizing, although not in an entirely accurate way, that the entire region along the coast of southern Italy is part of a linked system of geological unrest:

Strabo Geographica V.4.9
‘But what Pindar says is more plausible, since he starts with the actual phenomena; for this whole channel, beginning at the Cumaean country and extending as far as Sicily, is full of fire, and has caverns deep down in the earth that form a single whole, connecting not only with one another but also with the mainland; and therefore, not only Aetna clearly has such a character as it is reported by all to have, but also the Lipari Islands, and the districts round about Dicaearchia, Neapolis, and Baiae, and the island of Pithecussae.’

Many of these islands that Strabo names were, in fact, actively erupting during this period of antiquity. The Pompeians would not have had to look far for examples of volcanic activity. The Aeolian Islands of Stromboli, Lipari and Vulcano were all active – Stromboli, or Thera in antiquity, had been continuously active for 2500 years. Livy described the emergence of new island between Lipari and Vulcano in 183 BC.

Aetna was continuously active for two millennia, with fifteen documented eruptions between 141-10 BC. An eruption in 44 BC was so catastrophic the ash cloud dimmed sunlight over Rome, and there was such concern over the harvest that the Senate appointed Cassius & Brutus to oversee the harvest – or so Plutarch wrote two hundred years later. And of course, Aetna was the subject of a didactic poem written in the Neronian period. Although the author is unknown, some scholars suspect it was the product of Lucilius Junior, who observed an eruption whilst serving as Nero’s procurator on Sicily. Perhaps coincidently, he had grown up near Vesuvius:

‘Aetna shall be my poetic theme and the fires that break from her hollow furnaces. My poem shall tell what those mighty causes are which roll conflagrations on their way, what it is that chafes at governance, or whirls the clamorous heat-currents.’

There is also a fair amount of physical evidence that has survived in the archaeological record that demonstrates that the inhabitants of the Bay of Naples were dealing with seismic activity regularly. Work carried out by the Herculaneum Conservation Project along the ancient coastline has revealed regular changes in the coastline and water levels as a result of bradyseism. Both the House of the Telephus Relief and the Suburban Baths had to block of access points to the structures in order to prevent flooding. Some have speculated that the changes in the water levels were also responsible for the abandonment (and eventual total submersion) of the Portus Iulius at Misenum. Built in 37 BC, it became impossible to use within twenty-five years, which shows how dramatically levels were changing in that period. This is still a massive problem in the area today.

What is compiled here is a relatively small sample of the evidence that existed in antiquity for seismic activity and the nature of a volcanic landscape. All things considered, it seems unlikely that the Pompeians didn’t have some inkling that they were living near a volcano, even if they were unsure of its dormancy. The idea that no one would have remained there had they known of Vesuvius’ potential for death and destruction is blatantly false – millions of Italians continue to live there today, despite a well documented and understood threat. Perhaps the reason for accepting this seemingly inevitable risk is best illustrated by Martial, who though lamenting the destruction of the region soon after AD 79, makes it clear it was well worth it:

Martial, Epigrams IV.44
‘This is Vesuvius, green yesterday with viny shades; here had the noble grape loaded the dripping vats; these ridges Bacchus loved more than the hills of Nysa; on this mount of late the Satyrs set afoot their dances; this was the haunt of Venus, more pleasant to her than Lacedaemon; this spot was made glorious by the fame of Hercules. All lies drowned in fire and melancholy ash; even the gods could have wished this had not been permitted them.’


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