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THE STAGES OF ERUPTION MT VESUVIUS
Transcript of THE STAGES OF ERUPTION MT VESUVIUS
WRITTEN & PRESENTED BY ALISON, SAMANTHA & ANTHONY
For Romans living around the bay of Naples in Southern Italy, Vesuvius was considered as just a fertile mountain. Although it had been active in the 8th century BC it had been dormant ever since, leaving the people of the cities with a false sense of security.
Violent earthquakes in AD 62 and 63 were caused as the gases which had built up within the cone tried to force their way out.
In AD 79 the pressure had built up again, and the thick layer of lava, hardened to form a plug in the crater, was enough to contain the gases. For several days these had been earth tremors affecting the surrounding area.
The eruption of Vesuvius was documented by an eyewitness, Pliny the Younger (about AD 61–112) who watched from his mother’s house at the top of the Bay of Naples at Cape Misenum. He wrote two letters in which he narrated the events of the day and their effect.
PLINY THE YOUNGER
STAGES OF THE ERUPTION
MORNING - 8AM
A series of small emissions from Mt Vesuvius
- for several days previously there had been earth tremors.
MIDDAY - 1PM-3PM
After several small explosions Vesuvius erupts, sending a tall mushroom cloud of superheated rock and gas over 20km into the sky. The cloud blows southwards, plunging everything into total darkness.
"About one in the afternoon… a cloud was ascending, the appearance which I cannot give you a more exact description of than by likening it to that of a pine tree, for it shot up to a great height in the form of a very tall trunk, which spread itself out at the top into a sort of branches; occasioned, I imagine, either by a sudden gust of air that impelled it, the force of which decreased as it advanced upwards, or the cloud itself being pressed back again by its own weight, expanded in the manner I have mentioned; it appeared sometimes bright and sometimes dark and spotted, according as it was either more or less impregnated with earth and cinders."
Pliny the Younger describes the Vesuvius eruption
MIDDAY VIDEO - ERUPTION
The mountain emits noxious gases and unearthly noises. Violent tremors cause buildings to collapse. People flee to the beach, hoping for rescue from the sea but floating banks of pumice prevent ships from reaching or leaving the shore.
EVENING - 5-6PM
Pumice plummets from the cloud. Streets and roads are buried deep under the pumice and ash. Roofs of Pompeii buildings begin to collapse under the weight. The dense cloud now rises 25km above Vesuvius, obliterating the sun.
''The ashes now began to fall upon us, though in no great quantity. I looked back; a dense dark mist seemed to be following us, spreading itself over the country like a cloud… We had scarcely sat down when night came upon us, not such as we have when the sky is cloudy, or when there is no moon, but that of a room when it is shut up, and all the lights put out. You might hear the shrieks of women, the screams of children, and the shouts of men; some calling for their children, others for their parents, others for their husbands, and seeking to recognise each other by the voices that replied; one lamenting his own fate, another that of his family; some wishing to die, from the very fear of dying; some lifting their hands to the gods; but the greater part convinced that there were now no gods at all, and that the final endless night of which we have heard had come upon the world."
EVENING - ERUPTION VIDEO
The residents of the cities met death in different ways and at different times but many of them shared the basic instinct, as they fled, to take things with them that they believed were useful.
The eruption reaches its peak and unleashes a hurricane of heavier, denser pumice. This causes the widespread collapse of buildings and destabilises the volcanic cloud, triggering the first deadly pyroclastic surge.
MIDNIGHT - 12-2AM
Mid flows of volcanic debris from the volcano spill down the slopes, choking the town of Herculaneum. Ash, lapilli and Pumice continue to rain down on Pompeii. The debris is now rising as high as the upper stories buildings. It bursts through windows, doors, trapping and suffocating those hiding within.
MIDNIGHT - ERUPTION VIDEO
The cloud reaches its maximum height of over 30km then collapses spectacularly.
A massive pyroclastic surge cascades down Vesuvius’s north-west slopes. It heads for Herculaneum, instantly killing everyone it touches.
"It now grew rather lighter, which we imagined to be rather the forerunner of an approaching burst of flames (as in truth it was) than the return of day:
however, the fire fell at a distance from us: then again we were immersed in thick darkness, and a heavy shower of ashes rained upon us, which we were obliged every now and then to stand up to shake off, otherwise we should have been crushed and buried in the heap.
I might boast that, during all this scene of horror, not a sigh, or expression of fear, escaped me, had not my support been grounded in that miserable, though mighty, consolation, that all mankind were involved in the same calamity and that I was perishing with the world itself. "
EARY MORNING - 4AM-8AM
The volcanic plume above Vesuvius, now 30km high grows too heavy and begins to collapse. Sending superheated ash and gases down the volcano's slopes. Darkness prevails as the massive ash cloud hides the rising sun.
EARLY MORNING - ERUPTION VIDEO
As dawn breaks, the cloud collapses for the last time.
Between 4:00 and 8:00 huge pyroclastic surges pour onto Pompeii killing everyone still there and smashing remaining buildings. The cloud collapses for the last time and darkness spreads across the Bay of Naples.
"At last this dreadful darkness was dissipated by degrees, like a cloud or smoke; the real day returned, and even the sun shone out, though with a lurid light, like when an eclipse is coming on. Every object that presented itself to our eyes (which were extremely weakened) seemed changed, being covered deep with ashes as if with snow. "
Some people wore jewellery featuring good luck symbols, perhaps to invoke the protection of the gods as the city around them was destroyed.
Practical objects included lamps and lanterns
– essential during any evening but also, in these exceptional circumstances, during the day. The darkness in Herculaneum, and particularly Pompeii, overshadowed by the volcanic cloud, must have been near total. The lanterns they carried were fuelled by olive oil stored in the cylindrical reservoir at the base, and originally had shades made of thin sheets of animal horn.
As the eruption engulfed the cities, many of the people fleeing for their lives paused to grab objects of value such as jewellery and coins.
Perhaps they hoped to provide a safeguard against difficult times ahead.
This wicker basket, full of bronze coins and a handful of silver denarii, might have been a morning’s takings from a shop or bar.
Fused mass of coins, once contained in a wicker basket
City of Vesuvius - Pompeii & Herculaneum
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Lessing, E & Varonne A, 1996. Pompeii 1st ed,
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British Museum - Eruption timeline . 2014. British Museum - Eruption timeline .
History and eruptions. 2014. History and eruptions. http://www.vesuvioinrete.it/e_storia.htm.
Mount Vesuvius, Italy: Map, Facts, Eruption Pictures, Pompeii. 2014. Mount Vesuvius, Italy: Map, Facts, Eruption Pictures, Pompeii.