The 24th August AD 79 is traditionally believed to have been the eruption of Mount Vesuvius that wiped out numerous Roman settlements including Pompeii and Herculaneum. Eyewitness accounts of the eruption have survived in the shape of two letters from Pliny the Younger, and the discovery of the astoundingly well-preserved settlements has provided astoundingly detailed evidence about daily Roman life.
It should be noted that there is considerable debate over the accuracy of this date due to archaeological discoveries and recent meteorological research, but the majority of scholars continue to favour the 24th August. This, by unnerving coincidence, was just one day after the annual Roman festival of Vulcanalia, which was held to honour the Roman god of fire.
It’s known that the eruption lasted for two whole days, and released thermal energy that was hundreds of thousands times greater than the atomic bomb. Beginning at around 1pm on the 24th August, Vesuvius sent gas, volcanic ash, and pumice into the stratosphere for up to 20 hours. This was followed by a pyroclastic flow, which carried gas and molten rock down from the volcano and which then buried the previously fallen ash.
It’s believed that the majority of the 1,500 people whose remains or impressions have been discovered died of thermal shock during one of the pyroclastic surges. Others may have suffocated, or been hit by falling rocks and collapsing buildings. There is still a lot of archaeological work to be done, especially at Herculaneum, but digging has been put on hold to focus on the preservation of the areas already uncovered.
On the 23rd January 1556, the deadliest earthquake ever recorded hit the Chinese province of Shaanxi (pronounced Shensi) and surrounding areas. Scientists have since judged that the earthquake had a magnitude of around 8.0 on the Richter scale, and have had no reason to question the traditional estimates of around 830,000 deaths. Gaspar da Cruz, the Portuguese Dominican friar who in 1569 published one of the first books on China since Marco Polo, suggested that the earthquake was possibly God’s punishment for sinful behaviour.
The Shaanxi earthquake, while being the deadliest on record, was by no means the highest magnitude ever recorded. However, a 520 mile wide area was seriously affected and up to 60% of the population of some cities were wiped out.
The reasons for this level of destruction were the joint factors of location and timing. Firstly, by striking in the middle of a relatively densely populated area as a result of Shaanxi’s position as one of the cradles of Chinese civilisation, a large number of people were bound to be affected. Secondly, the people of the time predominantly set up home in fragile cave-like structures known as yaodongs that were dug out of the loess soil that covers much of the area. This silty sediment built up through the action of the wind, and while highly effective as an insulator it is also incredibly fragile. Referred to by agricultural and biosystems engineer John M. Laflen as the “most highly erodible soil on earth” some settlements were dug entirely from it. Consequently, the force of earthquake – and the landslides that followed – destroyed huge numbers of these dwellings.