Recently I took two earlier podcasts I had recorded and combined into one single Pompeii podcast, it covers the history of Pompeii and the events of the eruption. If you can forgive my mispronouncing of ‘pumice’ then I think, or rather hope, you’ll find it an interesting listen. You can listen to it on iTunes and other platforms. Alternatively, just click on the below player (technology eh?).
In this article I look at what happened on the 24th and 25th of August AD 79 and how you might have experienced the eruption. Spoiler alert, it’s not pretty and a couple of the images might cause some distress, but I hope you can see why I included them.
I should also respect the debate around the date of Vesuvius’ eruption. I deal with this in the podcast, but there are arguments which place the eruption as later than the 24th August and it’s good to appreciate that even widely held dates in antiquity are not beyond examination. For the purpose of this article we’ll accept the mainstream date as correct. So what happened exactly?
Sunrise at this time of year is around 06:30 which means that for many the day had already started. Residents may have noticed a few small puffs from the mountain, or perhaps not. Vesuvius wasn’t an active volcano and to those in Pompeii it was simply a large mountain, a dominating feature but one which had very fertile slopes.
Soon things developed; in the early afternoon, around 13:00 Vesuvius erupted proper (the thermal energy released was the equivalent of 100,000 Hiroshimas). Initially the force and energy went upwards, the ash column eventually reaching a height of around 20 miles (Felix Baumgartner’s freefall would have started only 4 miles above it). For the more recent reader who doesn’t want to look Felix up on google, the cruising altitude of most commercial aircraft is 5.5-7.5 miles high.
And there it stood, a huge warning beacon of what was to come. As the column reached higher it flattened out, an umbrella guaranteeing not safety from the elements but doom.
The wind direction blew the pumice mainly to the south
After half an hour pumice started falling. I can’t imagine many people consider pumice as lethal, perhaps to dead skin on feet, but not really something to shriek in terror from. Perhaps those in Pompeii were concerned but considered this as bad as it was going to get? They were wrong, if you wanted to leave this was going to be your last opportunity.
Pumice fell at a rate of around 15cm/h. This doesn’t sound much but it’s estimated that 40cms (16″) of pumice on a roof would cause it to collapse, here was the early threat. Those who had rushed inside to avoid the hot debris (anything over 1.6cm in diameter would have been warm, the larger the debris the hotter) may have initially found shelter. But by late afternoon the roofs of buildings would be starting to collapse under the weight. Homes now became tombs.
One study estimated that 38% of the victims of Vesuvius died this way (approximately 394 people), smashed foreheads and rubble giving a clue as to their demise. If the falling masonry killed you outright you might be lucky, as mentioned the debris was hot (the pumice heating the roof tiles to 120–140 °C), some trapped underneath may have been slowly cooked alive. Fires would have broken out in the darkness which now engulfed the city. Come late afternoon escape would have been nigh on impossible, the ash cloud now blotted out any light and most routes were choked with large amounts ash, pumice, bodies and rubble. Those left in Pompeii were trapped.
It’s early morning on the 25th and the pumice stops falling, assuming you could notice. The heat and dust in the air lowered both moisture and oxygen, meaning that anyone alive would be gasping for breath. Then came the knockout punch.
The volcanic column firing into the sky had destabilised and started to fail, the column now collapsed in six instances, each becoming a pyroclastic density current (PDC) or pyroclastic flow.
This is an avalanche of super-heated gas, ash and rocks, travelling up to 450 mph (700 km/h) and heated up to 1,000 °C (1,830 °F). According to this study the PDCs which reached Pompeii travelled quite slowly, (18-28 mph) but they were still incredibly hot, and it was the heat which was the primary cause of deaths. At Pompeii it’s estimated that the temperature reached 250°–300°C.
Of the six PDCs the first three had either not reached Pompeii or had been stayed by the north wall. It was the fourth PDC, arriving at dawn on the 25th, which breached the wall and ended anyone who had until that time survived. The saving grace was that given the temperature death resulted in fractions of a second.
Herculaneum was spared the initial fall of pumice, the winds that day blowing the cloud over in the direction of Pompeii. There must have been an acceptance that something wasn’t right, even without the pumice the noise and sight of the eruption seems to have incited the locals to flee. We know this because of where many of the remains of the inhabitants were found, not in the houses but in the arches on the coastline of the day. Several hundred bodies were found, presumably waiting for an opportunity to escape. Those who had managed to get on a boat before midnight after the eruption had started may have stood a chance. Those who hadn’t were met at 01:00 on the 25th by the first PDC following the collapse of the column.
Not only did Herculaneum receive the first PDC in full force, it was hotter, reaching 500˚C (according to this study). The very definition of overkill.
For anyone who has seen the casts of the victims of Pompeii you might ask how they met their fate. One common stance seen was one where the victim held their hands out in front of them, the initial diagnosis of this was that these were people defending themselves from looters. I suppose this has traction, except the more you consider it. Would looters be operating in pitch blackness? Why would anyone want to loot in this situation, surely you would want to get away?
Of course, it is feasible that some in Pompeii might have availed themselves to opportune theft. But surely the ongoing situation might stay a pilfering hand and instead surviving was at a premium. Fortunately science was able to offer an alternative.
In the first instance we need to familiarise ourselves with the term ‘the pugilistic pose’ or ‘pugilistic posture’ as it’s also referred to. One online medical dictionary I came across defines it thus:
A ‘defensive’ position fancifully likened to that adopted by pugilists (boxers), which is typically seen in severely burned bodies, characterised by flexion of elbows, knees, hip, and neck, and clenching of hand into a fist; it is caused by high-temperatures in fire, resulting in muscle stiffening and shortening; it occurs even if the person was dead before the fire.
The PDCs which hit both Pompeii and Herculaneum had this in abundance. Many of the casts at Pompeii (according to this study) 64% exhibit this posture. Volcanoes weren’t just a thing of BC, they erupt even today. Below is an example of the pugilistic pose in a victim of the Merapi eruption in 2010
Compare this to a victim from Pompeii:
In the image from Pompeii the two victims assume similar positions, albeit one supine and one prone. Both are similar in posture to the victim from Merapi.
Understanding the stages of the eruption allows us to fully realise the differing ends which those there met. Yet amongst the macabre statistics there is reason for optimism. In her book on Pompeii Professor Mary Beard suggests a population ranging between 6,400 and 30,000 in Pompeii at this time. It’s estimated that 2,000 at most died (Pompeii is still being excavated). If we take a middling figure of 15,000 and make the obvious assumption that no-one survived it suggests the majority of the residents had left prior to the main eruption.
This brings in two wider points, the first that those residing there had realised something was up in the period leading to the eruption. Even without scientific equipment the signs could have been evident, Seneca mentioned sheep poisoned by a poisoned cloud after the earthquake of AD62 and perhaps there were similar signs here. Carbon dioxide is known to be released by volcanoes, especially by ones about to erupt. However, it’s unlikely any Pompeiian would have diagnosed an eruption and instead memories of the catastrophic earthquake of AD62 might have come to mind. In short perhaps people realised something was up and decided to leave.
The second point leads on from this, Pompeii offers a paradox in that we rely on it for a glimpse of life in antiquity a snapshot of life in AD79 which was frozen and left for later eyes to find it. Yet it may mislead the eye more than direct it. If we consider the mass movement of residents to what extent does this change what’s left. Think of a rich family leaving in the time prior to the eruption, they take their prized goods with them leaving little behind. How are we to understand their residence once it is uncovered? A normal residence or one which anyone of the time would think of as empty?
Added to this is that Pompeii wasn’t sealed in time till it was rediscovered in the modern times. There are small tunnels which were dug by those looking for trinkets to steal and sell, some walls even had ‘tunnelled’ written on them by later generations. The skeleton of a child was discovered in one such tunnel, the tragic victim of a collapse.
Having visited Pompeii it feels very much woven with contradiction, here’s a place of disaster and mass loss of life yet it sidesteps this and urges you to walk with inquisitive strides, seemingly in defiance of this single inescapable fact. It’s incredibly detailed, with jaw-dropping views and round the corner obscene graffiti.
All of this and there’s still more to excavate, who knows what might be found, which gives Pompeii another twist in its story. Not all secrets stay in the grave.