Eruption of Vesuvius on Herculaneum ‘like Hiroshima bomb’

[Imperial Dave]

https://www.theguardian.com/science/2021/dec/01/eruption-of-vesuvius-on-herculaneum-like-hiroshima-bomb-pompei?CMP=Share_iOSApp_Other

no surprise really...

[Ian61]

An interesting article but there has been lots of research on pyroclastic flows in the last century and there are many other more recent examples. I remember reading a book about them which used the 1902 eruption of Mont Pelee in the Caribbean as the primary example, the flow hit the city of St. Pierre (I have just checked, that killed 30,000 people) but with a number of others in more well recorded recent time mentioned along with the Vesuvius eruption.
The analogy is all very well but seems to be for headline grabbing, nature can be far more terrible than most people living in geologically stable Britain think.
The thing I find difficult to get my head around is that standing at the entrance before going down into Herculaneum you are almost vertically above the ancient shore line looking down on a two story building. But if you look up and around you are confronted with numerous four(?) story blocks of flats of the modern town and wonder why on earth people would choose to live there. (I know there are some good agricultural reasons with the fertile soils etc. but I doubt that those flats are all filled with farm workers and their families!)

[Nick Harbud]

Well, this article just about meets one's expectations of the Grauniad's journalistic standards.

How similar is a volcanic eruption to a nuclear explosion? 

Well, the amounts of energy released are comparable with the volcano outstripping the bomb by a significant amount, but Vesuvius released it's energy over a couple of days instead of seconds.

Vesuvius's pyroplastic flows were certainly very hot, leaving impressions of bodies in the ash deposits, yet the bomb left only shadows.

Just over 1,000 bodies have been identified as certain casualties from Vesuvius.  There were undoubtedly more deaths.  However, many people evacuated and saved themselves during the early stages of the eruption.  So, the total body count was nowhere near the 129,000-226,000 deaths estimated for the Hiroshima and Nagasaki explosions.  And, of course, in the latter case a further 150,000-220,000 (more than a third of the population) are estimated to have died from radiation poisoning during 1945.

Horrific though it undoubtedly was, IMHO the Vesuvius eruption was nothing like an atomic bomb.

Incidentally, the largest man-made pre-nuclear explosion occurred in 1917 at Halifax, Nova Scotia.  This has been estimated at 2.9 kilotons of TNT, approximately 20% the size of the Hiroshima bomb.  It killed approximately 2,000 and wounded a further 9,000.  The Wikipedia page gives quite a good description for those interested in how it led to improved treatment of eye injuries.

Hope this puts things in perspective.

[Duncan Head]

The article shows no sign that it does not accurately reflect the statements of the Italian archaeologist quoted, so any criticism should be directed at him rather than the Guardian.

Otherwise, well done for explaining differences that have no bearing on the similarities in the state of the bodies that are the basis for Camardo's comparison.

[Jim Webster]

Compared to Krakatoa it barely registers

[Nick Harbud]

The article shows no sign that it does not accurately reflect the statements of the Italian archaeologist quoted, so any criticism should be directed at him rather than the Guardian.

Balanced journalism does not merely reproduce the statements of one person, but also outlines any opposing arguements.  To take a more modern example, would you consider it good journalism to report President Jair Bolsonaro's assertion that covid-19 vaccinations increase the probability of contracting AIDS without also noting that scientists and medical experts consider this to be complete nonsense?

[Imperial Dave]

https://www.heritagedaily.com/2021/12/archaeologists-find-victim-of-vesuvius-eruption-on-herculaneum-beach/142152

[Nick Harbud]

For those interested in Jim's comparison with the Krakatoa explosion in 1883, Wikipedia contains a handy table.

[Imperial Dave]

so not the biggest then

[simonw]

The eruption of Vesuvius that destroyed (and preserved) Pompeii and Herculaneum is the 'archetypical' 'Plinian' type (as it was described by Pliny the Younger who observed it at the time).  It comprised a highly explosive eruption hurling ashes, gases, steam and 'bombs' high into the sky until the force of the eruption diminishes to an extent that the bulk of the solid material suspended in the massive column of extruded material collapses back to the ground. This is what then generates the pyroclastic flows and makes them so dangerously fast.

"The column of volcanic pumice, hot gasses and ash, pushed upwards of 9 miles into the atmosphere and spread across the skyline like black ink on blotting paper. Pliny described its general appearance as 'like an umbrella pine tree, for it rose to a great height on a sort of trunk and then split off into branches."

"Every second one and half million tons of volcanic debris spewed into the atmosphere, regurgitated from the fiery depths of the raging giant. That day, Mount Vesuvius released over 100,000 times the thermal energy of the two atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki during WWII."

So the town of Pompeii suffered primarily from wind-blown ash fall in the initial stages of the eruption which crushed and buried the town and some those inhabitants that didn't flee immediately.

Herculaneum on the other hand, didn't experience much ash fall during the first stage of the eruption as it was more up-wind of the ash cloud BUT was hit by a major pyroclastic flow several hours after (maybe as much as a day after), the eruption began. The inhabitants there would have not until very late of the risk that they were facing and so more did not evacuate in time. When they pyroclastic flow hit Herculaneum, the effects on the population were akin to that of a thermonuclear bomb in that they were killed virtually instantaneously if caught by the flow.

So the modes of destruction and preservation at Herculaneum and Pompeii were actually different to a significant degree with Herculaneum being virtually instantaneously flash-fried and buried whereas at Pompeii, the town was largely buried more slowly by falling ash over a relatively lengthy period of time.

So I think that's the gist of what the archaeologist was trying to get at.  Either way, the actual 'force' of the eruption was directed upwards as the volcano blew cubic kilometres of its top into the sky. It wasn't a 'lateral' blast wave of a nuclear bomb that destroyed Herculaneum and Pompeii, it was gravity!