On the morning of August 24, 79 (CE) and continuing through the next day, Mount Vesuvius rained down fire and brimstone on Stabiae, Herculaneum, and—most famously—Pompeii, freezing homes and monuments and bodies in time for centuries. Today is the one thousand, nine hundred thirty-eighth anniversary of that cataclysmic eruption that so thoroughly obliterated the cities that sat in its shadow that, for over a millennium, history forgot where Pompeii stood.

Mount Vesuvius is a somma-stratovolcano—basically, Vesuvius is comprised of layers upon layers of different materials and it is the newer cone that sprouted out of the collapsed caldera of a more ancient volcano named Mount Somma. In fact, the half-ring summit embracing Vesuvius is the part of the rim of Mount Somma’s caldera wall that time and elements have yet to erode away. Somma’s caldera collapse and Vesuvius’ subsequent birth occurred some seventeen thousand years ago—the eruptions that caused Somma’s cone to collapse into a caldera were of the same type but significantly more violent than Vesuvius’ 79 eruption. Named after the only eyewitness account of the eruption that decimated the Campania region of Italy—Pliny the Younger—, plinian eruptions are characterized by the enormous columns of noxious gas and volcanic ash, continues gas eruptions, and sheer volume of pumice ejected from the cone. Pliny the Younger described the eruption in a letter:

“…its general appearance can best be expressed as being like an umbrella pine, for it rose to a great height on a sort of trunk and then split off into branches, I imagine because it was thrust upwards by the first blast and then left unsupported as the pressure subsided, or else it was borne down by its own weight so that it spread out and gradually dispersed. In places it looked white, elsewhere blotched and dirty, according to the amount of soil and ashes it carried with it.”

Plinian eruption of Chile’s Cabulco Volcano in April 2015

Plinian eruptions are the most violent and dangerous type of volcanic eruptions, throwing hot gas, ash, and pumice and other tephra miles into the air. The column rising from the volcano’s cone will periodically collapse resulting in pyroclastic flows—dense mass of hot ash, gas, a lava fragments moving down the slope of the volcano at hurricane-force speeds—and volcanic mudflows known as lahars. Vesuvius’ 79 eruption was the prototypical Plinian eruption and all of the dangers associated with those eruptions are likely to blame for the devastation wrought in those forty-eight hours.

Credit: U.S. Geological Survey/original illustration from Myers and Brantley

There were some telltale signs of the violence Vesuvius was about to visit upon Campania: animals behaving strangely, plants and animals mysteriously dying, constant tremors, wells running dry. You know, the standard precursors to being smote by the bowels of the planet.

The standard portents of doom gave the people living in cities at the base of the volcano a jumpstart—many of them evacuating well before the eruption on August 24th. Additionally, the only not terrible thing about it being a Plinian eruption was the simple fact that it bought some folks a little extra time to get out of Dodge had they not evacuated beforehand. At least, it bought the people who could afford to evacuate extra time to do so; as with all natural disasters, the mostly likely to be well and thoroughly screwed were the poorer residents of Stabiae, Pompeii, and Herculaneum.

Photo by Bill Chizek. Vesuvius looming behind modern-day Naples.

Those who were left behind, it seems, did not suffer long, agonizing deaths. Rather, it appears that the vast majority of those left behind died nearly instantaneously upon the arrival of the first pyroclastic surge to hit each city—the temperature of the surge was so high that it killed within fractions of a second. Because of the volcanic ash and debris that covered the decimated cities, skeletons and the shapes of the bodies were preserved in the exact position they were in at death and none of them thus far seem to show any signs of death by asphyxia, which was the assumed cause of death for many years. Preserved skeletons and plaster casts of the empty spaces where bodies once were revealed many in repose or cuddling a lover or a child …or *ahem* otherwise spending time with a loved one.

The more things change, the more they stay the same.

In the nearly-two thousand years since the calamity that befell the Bay of Naples, Vesuvius has never quieted down for too long—in geological terms, anyway. There was a period of relative peace—from the end of the thirteenth century to the early-middle of the seventeenth century—that saw Somma-Vesuvius covered in foliage and vineyards and gardens. Then, in 1631, Vesuvius erupted again, killing some three thousand people with its lava flows and lahars. Until recently, it had been pretty continuously active since the seventeenth century. The most recent significant eruption occurred in 1944.

“It vies with war for diabolical supremacy.”Damn.

Now, nearly two thousand years after the destruction of Pompeii, millions of Italians live in the shadow of Vesuvius. According to the geological record, Somma-Vesuvius unleashes a disastrous, Plinian eruption approximately every two thousand years. And in terms of geological time tables, we are within the window allowed for by that approximation. In response, the Italian government has been working on a preparedness plan focusing on evacuating the hundreds of thousands of residents that live within the “red zone,” the area immediately surrounding Vesuvius that is at the highest risk of experiencing pyroclastic flows.

So, on the anniversary of the annihilation of Herculaneum, Pompeii, and Stabiae, let’s take the opportunity to appreciate humanity’s always having been humanity, to learn about life in the Bay of Naples in the first century, and to contemplate the awesome power of destruction (and eventual creation) that lies beneath our feet. Thinking on August 24, 79 (CE) is sobering, awesome, and terrible.

And, yes, a little bit funny too.



Promo source: https://commons.wikimedia.org/wiki/File:Mount_Vesuvius,_Pompei_-_panoramio.jpg
Photo 3. Licensing info: https://commons.wikimedia.org/wiki/File:Mount_Vesuvius_in_Naples,_Italy,_Napoli1.jpg

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