The eruption of Vesuvius in 79 AD, what happened in Pompeii and Herculaneum

Vesuvius awoke at nine in the morning of 24 August, however, the eruption itself started only around one in the afternoon. Inside the volcano opened a duct caused by a series of explosions due to the sudden transformation into gas water coming in contact with the rising magma. Following a column of gas, ash, pumice and pyroclastic fragments lifted for about 15-20 km above the volcano and created a cloud feature that darkened the sun. Pliny described it from Misenum , at a distance of 21 km from the volcano , and was able to observe the eruption column throughout its development. Depicted by pointing to the shape of a pine tree, with the smoke that was dissolved on its own weight. The writer noted that the column was sometimes white, sometimes instead was dirty and stained, depending on who had raised himself with earth or ashes. photo: Pompeii and Herculaneum fell off, a hellish rain bringer of death fell from the column Plinian pumice towards Pompeii , where in a short time accumulated to form a layer about 4 feet high that buried the entire city. now, while falling pumice, someone left in a hurry the city, others completely unaware of what was happening, hid in cellars and in the most sheltered. They died unaware, in the shadows created by the cloud that had obscured the sun in the hours following suffocated from heat and toxic gases when the first big flow reached the city. Upon Ercolano , however, the situation was quite different: up at eight o'clock the next morning rained only a thin ash and although there were frequent earthquakes, the city was spared for many hours of the disaster. Now, the locals have had plenty of time to save themselves if only they had imagined what would happen in the next few hours, however, in the night, rather than leave the area, taking advantage of a break akin eruptive activity, many people did return to their houses that had been left unattended. And that cost him dearly. After eight o'clock in the morning of 25 August, in fact, volcanic activity resumed with the formation of the column button, where they alternated emission of ash flows and pyroclastic surge . Both pyroclastic flows both surge develop when the magma flow, reaching the crater, rises to become too abundant to form an eruption column capable of rising above the volcano. The collapse of a column dense and heavy, which can also affect only its outer zones, conveys the gas mixture and fragments of solidified magma and rocks downwards. Are formed in this way flows of volcanic material flowing down to the ground and fast along the flanks of the volcano. Passing over the city of this flow was disastrous. Thick walls and entire walls perpendicular to its path were overthrown in equity, as were swept away the roofs and the last floors that still held up. The volcanic material swirled with a speed of about 100 mph, dragging a large quantity of crushed stone, plaster, beams and roof of the buildings destroyed. His fury burst out from those who still resisted the shelter of the most isolated refuges. And after this flow, the whole area around Vesuvius became like a desert gray. photo: who remained in the areas affected by the volcano came to an inglorious end ... But there's more. tsunami waves caused by magmatic material in the finished sea ​​overwhelm the few survivors fell on the beaches in search of safety. But the boats anchored in the harbor are on fire and the sea water boils. 's the last phase of the disaster. flows ending at around 10.30 on 25 August and the water from underground poured on the rocks heated by magma , causing a succession of violent explosions that shake the volcano for some time. At nightfall of the second day, the eruptive activity began to decline rapidly until they ceased altogether. eruption had lasted little more than 25 hours , during which the volcano had expelled nearly one billion cubic meters of material.