Would You Survive?
The volcanic eruption of Mount Vesuvius in A.D. 79 caught most of the Roman population off guard. Would you have made it?
Warning Signs: What would have been your first sign that an eruption of Mount Vesuvius was imminent?
All the animals were fleeing the area.
Earthquakes throughout the region signaled the volcano was becoming active.
The sky darkened and the smell of sulfur was strong.
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As the pressure within the volcano built, earthquake activity, in the form of harmonic tremors, increased, signaling the volcano was roaring back to life.
Warning Signs: If you, like other Romans of the time, had known about the history of Mount Vesuvius, would the information have helped you survive?
No, there were no previous eruptions.
Yes. You would have known about two earlier catastrophic eruptions that wiped out entire populations.
No, previous eruptions were so different and insignificant that the information would have been meaningless.
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The most important earlier eruption, the "Avelino pumice," occurred around 1800 B.C. and destroyed Bronze Age settlements. Had the Romans known about this, they might have avoided the deadly surprise.
Warning Signs: Mount Vesuvius had been dormant for eons before the eruption of A.D. 79. Did this make its eruption more or less dangerous?
More dangerous. A long interval, combined with mounting seismic activity, is a sure sign of impending disaster.
Less dangerous. More time actually allows the seismic pressure to disseminate, causing the volcano to lapse into dormancy.
Neither. Lapsed time has no effect on a volcanic eruption's intensity.
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The catastrophic magnitude of the eruption was directly connected to the extended period of inactivity that preceded it.
Winds of Chance: On the day of the eruption, the wind blew inland from the southeast across the Bay of Naples. Had the winds been from the north out to sea, as was usual, would you have experienced less devastation?
No, the winds make little difference in volcanic eruptions.
No, the force of the eruption was so severe nothing was going to curtail its destructive force.
Yes, the wind would have blown the volcano's debris column out over the bay, where it would have done less damage.
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The unusual wind pattern and the nature of the eruption combined for destructive force. Had the winds been blowing out into the bay, much more of the debris would have fallen into the sea.
Winds of Chance: The volcano erupts, blasting a column of boiling rock and gas into the air. Soon, a light hail of pebbles begins to fall. What is this? And should it cause immediate concern?
No, this is merely the first thrust of the volcano; the real danger is the hot pyroclastic flows to follow.
Yes, these are known as the "fire rocks" and can cause severe burns.
Yes, these light pumice stones are mixed with much deadlier heavier volcanic rock.
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As the column of boiling rock and gas cools in the atmosphere, pumice stones form. Although these relatively-light stones will collapse roofs, the immediate danger is the heavier volcanic rock.
Winds of Chance: What is this heavier rock mixed in with the lighter pumice stones? And why is it so dangerous?
Limestone: Although it's heavier, the real danger lies in its superheated, gelatinous mass.
Lithics: Cold, dense rock fragments torm from the interior of the volcano.
Blastophites: Dense, loosely packed volcanic matter that explodes on contact like a fiery dirt clod.
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Lithics are dense rock matter ejected out of the volcano that hurl back to Earth like missiles.
Pliny's Legacy: The eruption of Mount Vesuvius was far more deadly than most volcanic eruptions. Why?
Magma and superheated gas and ash formed a gigantic column in the atmosphere.
Fiery molten lava was spattered over such a large area.
Severe earthquakes accompanied the eruption, causing just as much damage.
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These so-called Plinian eruptions release superheated gas, ash and magma into the atmosphere, and ground-hugging pyroclastic surges that incinerate everything in their path.
Pliny's Legacy: Why ARE eruptions like that of Mount Vesuvius called Plinian eruptions?
They are named for the composition of the magma ejected from the volcano.
They are named for the shape of a pine tree, which the plume cloud resembles.
They are named for the first person to record the phenomena.
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The eruption is named for Pliny the Younger, who witnessed the Vesuvius eruption and described the massive gas-and-ash cloud that destroyed Pompeii.
Pliny's Legacy: In order to survive the eruption, where is the safest place to avoid the volcano's tephra?
In the water, where it becomes harmless.
Under a well-fortified overhanging or cover.
On high ground, where it is unlikely to reach you.
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"Tephra" is the generic term for all air-fall material ejected by a volcano. The safest place is under cover, though many structures still collapse under its weight.
Can You Run To Safety? You are still in Pompeii, and the pumice stones are falling heavily now. What is your best course of action?
Stay where you are and wait for help.
Find the lowest, most fortified space and cover yourself with blankets.
Evacuate quickly and carefully as you need to get as far from the volcano as possible.
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Time is of the essence. Put distance between you and Vesuvius! At it's peak, the volcano is blasting out 100,000 tons of material per second, debris that will eventually fall back to Earth.
Can You Run To Safety? If you decide to make a run for it, what is the most important thing you should have with you?
Money, as you will need to purchase supplies.
Water, because uncontaminated water will become scarce.
All your treasured possessions, as everything left behind will be destroyed.
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The pumice and ash falling constantly not only contaminate the local water supply, but suck moisture from the air. You will need water above all else during the eruption to survive.
Can You Run To Safety? If you are fleeing from the base of Mount Vesuvius, in which direction should you go?
Head north into the country, where it is less congested.
Head south to the ocean and wait for rescue.
Head west toward Naples, where they are better prepared for the emergency.
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Your best bet is to go the least congested route. Those heading into Naples will still be within the volcano's reach. And most who head for the beaches will die before the help arrives.
Pyroclastic Problems: You would have little chance of surviving if you encounter a pyroclastic flow. Why?
It is a deadly ground-hugging avalanche of hot ash, pumice, rock fragments and volcanic gas.
It's a sudden, killer molten lava "river" that runs down the side of an active volcano.
It's a sudden chasm that opens up under your feet in the midst of an eruption or earthquake.
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A pyroclastic flow is a destructive volcanic avalanche that rushes down the side of a volcano much faster than a human can run.
Pyroclastic Problems: The first pyroclastic surge has incinerated many coastal towns. The second surge narrowly misses Pompeii. But if you didn't flee, this surge could kill you. How?
The intense heat is so sudden, it catches you unaware.
The surge is preceded by such a strong blast wave, it levels everything nearby.
The surge carries a cloud of toxic gas.
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Although the second surge narrowly misses Pompeii, it carries a toxic gas cloud that's lethal.
Pyroclastic Problems: The lethal combination of gases emitted from the eruption of Vesuvius was most likely a mix of?
Methane and carbon dioxide
Carbon dioxide and hydrogen chloride
Sulfur and hydrogen chloride
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Many who survived the volcano's fallout succumbed to its killer cocktail of carbon dioxide and hydrogen chloride.
What NOW? If you have survived the pumice hail, the first two superheated pyroclastic flows and the toxic gas cloud, are you FINALLY safe?
Yes, the volcano's eruption is nearly over.
No, but if you make a run for it now, you can likely escape the volcano's final wrath.
No, a third and final pyroclastic flow is the strongest and will bury Pompeii.
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If you are still in Pompeii at this point, you have no chance. The final pyroclastic flow will dump 30 feet of superheated ash and boiling rock on the town.
What NOW? After 18 hours of constant eruption, the volcano is nearly spent. The force of its upward thrust weakens. Is this the merciful end to the danger?
Yes. Once the eruption loses steam. the column of ash and gas will dissipate.
No. The end to the upward thrust simply means the ash cloud's tephra will begin to fall back to Earth.
Yes. With the end of the eruption and its destructive force weakening, the ash cloud will blow harmlessly out to sea.
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Without the upward thrust, the huge column of ash and volcanic debris in the atmosphere will begin to collapse, dropping its load over a wider path.
What NOW? Much has been made of the Vesuvius eruption because of the Pliny the Younger account and spectacular archaeological finds. But was it truly cataclysmic in terms of lives and property lost?
Yes. Thousands were killed, and Pompeii, Herculaneum and Stabiae were wiped from the Earth.
No. Though lives were lost, the death toll was relatively minor.
No. The area was lightly populated at the time. However, many glorious homes of wealthy Romans were destroyed.
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The remains of more than 2,000 Pompeiians have been excavated. But the area was, as now, densely populated, and it is assumed that more than 10,000 lives were lost.
Correct
Sorry, but you didn't know enough to survive. The volcano was too fast for you to evade.
Correct
You knew enough to survive, but the volcano was too fast for you to evade.
Correct
Congrats! You knew enough to survive and were fast enough to evade the volcano.
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