A huge cloud of ash and gases released by Vesuvius in 79 AD took about 15 minutes to kill the inhabitants of Pompeii.
Numerous studies have confirmed that the estimated 2000 people who died in the Roman city were suffocated rather than killed by the lava. And work by researchers from the University of Bari, in collaboration with the National Institute of Geophysics and Volcanology (INGV) and the British Geological Survey in Edinburgh, says the pyroclastic flow – a dense, fast-moving stream of solidified lava pieces, volcanic ash and hot gases – Pompeii engulfs just minutes after the volcano erupts.
The deadly cloud “had a temperature of more than 100 degrees and consisted of CO2, chlorides, light bulb particles and volcanic glass,” said Roberto Isaia, senior researcher at the Vesuvius Observatory of the INGV. ‘The aim of the work was to develop a model to try to understand and quantify the impact of pyroclastic flow on the inhabited area of Pompeii, about 10 km. [6 miles] of Vesuvius, ”he added.
The study confirms that the residents had no escape, and that most of those who died suffocated in their homes and beds, or in the streets and squares of the city. According to Isaiah’s model, the gases, ash and volcanic particles would have engulfed the city between 10 and 20 minutes.
“It is likely that dozens of people died as a result of the rain of lapillaries that fell on Pompeii after the eruption, but most of them died due to suffocation,” Isaiah said, adding that the pyroclastic flow Pompeii a few minutes after the explosion would have reached.
‘Those 15 minutes inside the infernal cloud were probably endless. The residents could not imagine what was happening. The Pompeians lived with earthquakes, but not with eruptions, so they were surprised and carried away by that glowing cloud of ashes. ”
The INGV research described pyroclastic currents as ‘the most devastating impact’ of explosive eruptions. ‘Similar to avalanches, it is generated by the collapse of the eruption column. The resulting volcanic ash runs up the slopes of the volcano at speeds of hundreds of kilometers per hour, at high temperatures and with a high concentration of particles. ”
Today, the ruins of Pompeii are next to the Colosseum in Rome, the second most visited archaeological site, and last year attracted about a million tourists.
“It is very important to be able to reconstruct what happened during Vesuvius’ eruptions in the past, from the geological record, to trace the characteristics of the pyroclastic currents and the impact on the population,” said Prof Pierfrancesco Dellino of the University of Bari said.
“The scientific approach adopted in this study reveals information contained in the pyroclastic deposits and which clarifies new aspects of the eruption of Pompeii and provides valuable insights into the interpretation of Vesuvius’ behavior, also in terms of civil protection.”