Ch.24: Eruption in Herculaneum

There was much discussion on the circumstances in which took place the burial of Herculaneum.  They differ greatly from those of the burial of Pompeii.  While for the latter, in fact, it happened, following the rain of lapilli and ash carried by the wind, a regular stratification eruptive material 5 to 6 meters maximum, Herculaneum, on the contrary, shapeless mass of materials, projected and accumulated around and on the edges of the crater, was driven by the huge volume of water from torrential rains always accompany major volcanic convulsions and down like a huge torrent of mud along the steep slope of the mountain, carrying and engulfing everything in its path.

The villas upstream first, and the city itself, then, were overwhelmed by this wonderful cast who, having invaded and filled all empty, completely transformed the appearance of the place.  In solidifying, this flood of muddy lava, which had managed to penetrate even the smallest gaps due to its semi-liquid state, took the appearance of a compact layer sometimes reaching the hardness of tufa, which it presents characters in a certain range (pappamonte) of unequal composition and strength along the various streams of the casting.  The thickness of the layer of mud and lava melee covered with topsoil, in which the city is buried varies da 12-18 meters and more.

Several scholars have questioned the circumstances.  They attribute the burial of Herculaneum, such as Pompeii, rain of ash and lapilli, the hardness of the ground is due to a simple precipitation of calcium carbonate.  This assumption clashes with positive data from excavations, such as: the dismantling of the upper stage and the cavea of the theater, with their largely overturned statues, the discovery of fragments of the same sculpture scattered at great distances from each other, the streets turned into rivers, the fact that we found local vaults filled to the top by the fluid mass that entered it by skylights.

But if the circumstances occurred burial made and make them extremely difficult excavations, however, they have helped preserve the city levies or looting after the disaster, to keep up the buildings and, thanks to the almost total impermeability and constant humidity of the land, to preserve also the wooden structures which in the old buildings have much more importance than the ruins reveal the other cities.

Activity between 79 and 1944 DC

Vesuvius is in the region of Campania, in southern Italy.  It overlooks Naples and the full Gulf of Naples. In extended wide, its slopes, starting from Naples, arriving to the province of Benevento and Salerno.  Long periods of inactivity alternate with periods of very high activity.  He entered the history of volcanology with the eruption of 79 AD the Roman or whole cities will be buried.  Activity begins with the formation of a tall column of gas, ash and lapilli, as described by Pliny, seeing it Misenum (20 km from the volcano), extreme eastern tip of the Gulf.

 "(...) The pine-shaped cloud rose high into the sky and expanded with branches emissions ...

Entire cities such as Pompeii, Herculaneum, Stabiae, Oplontis, Sarnum, Octavianum and many others will be destroyed.  The vulcaniques éruptés Vesuvius products cover the fields, filling the streets, houses and temples of the city.  After the eruption of Vesuvius in 79 graves a long silence and the first news of its activities are slow in coming.  Dion Cassius relates that a violent eruption in 203, whose screams are heard to Capua, 40 km of Vesuvius. News of two other major eruptions occur s'sont 472 and 512 declared by Marcellin Committee, Chancellor of the Emperor Justinian.  "Year 472" Vesuvius, torrid Bell Mountain fire burning inside, vomited her guts on fire, during the day he brought the shadow of a little dust on the surface of all the 'Europe ".

The eruption of 512 is described in detail by Cassiodorus, a Quaestor of King Theodoric, in a letter written to a tax exemption application for those affected by the eruption. He reports that "(...) A layer of ash that has burned, forming clouds, raindrops, dust even in provinces overseas (...). It 'can see ash flow like rivers pouring liquid slippery sand (...) Hot and rear wave fields until suddenly the treetops ... . Explosive eruptions, which occurred between 680 and 685, are given by Paul Deacon in the Historia Longobardorum and others are reported in 787 and 968. Leo Marsicano in the chronicles of the Abbey of Monte Cassino, speaking of the eruption 968, said "a big fire and unusual descended towards the sea ...".

In this eruption, there may be the first evidence of a lava flow, defined as "... sulfur resin rushing impetuously towards the sea continues ...".  Many authors speak of eruptions in 991, 993 and 999, but since then enveloped by the belief of an imminent end of the world, all references to disasters should be viewed with a degree of suspicion.  A chronicle of the Abbey of Monte Cassino indicates another eruption that lasted six days from January 27, 1037, and others with explosive events between 1068 and 1078. The last eruption before a long rest period occurs in early June 1139, it is reported in a chronicle of the Abbey of Monte Cassino, the Abbey of Cava dei Tirreni and the secretary of Pope Innocent II, Benevantano Falcone, who had written that Vesuvius "and threw ... for eight days powerful fire and flames ... ".  There is no known credible witnesses to the activity of Vesuvius from 1139. By about 1360, Boccaccio wrote that from Vesuvius " not let flames ... no smoking ...".

In an unspecified year of 1500, Ambrogio da Nola Leone reported a rash that lasts three days, which was followed by the formation of gas fumaroles. A Spanish soldier, who came to Mount Vesuvius in 1501 with Queen Isabella (.. De Castille ..), describes the crater "... a hole 25 to 30 feet in diameter & previous egr; ... large trees have grown in the Grand cone , the cone in the caldera Somma, and the whole apparatus was called Mount Somma, the name of the city that lies at the foot of Mount Vesuvius ... .. "

Defers an ancient manuscript. "... .In The night between 15 and 16 December 1631, among the strongest explosions and earthquakes, Vesuvius back in business with a catastrophic eruption that spread panic and destruction for several months, the whole area was plagued by frequent earthquakes, which had intesifié few days before the rash ... ".
 Giambattista Manso, writer who described the eruption cloud that rises partly to heaven (Plinian column) and partly growing on the slopes of the mountain like a torrent of pyroclastic flows. "... The most violent phase lasted three , stopping at goal five days, leaving a trace of mudslides and landslides of volcanic material accumulated on the slopes ... ".

The light emission of ash and earthquakes continued for months.  After these eruptions, Mount Vesuvius has completely changed shape: the cone exceeds the Mont Somme;  he was beheaded and the crater, according to Bouchard, a French scholar, has a diameter at its base of about two miles (about seven kilometers ..).
With the eruption of 1631 Vesuvius enters a phase of intense activity continues jousqu 'in 1944. Violent incidents were reported in 1794, 1822, 1834, 1850 and 1872.
 after a new eruption, Vesuvius cone reaches its maximum height of 1335 m

In May 1905 a new business, first with slow exit from lava, of January 1906, with intermittent explosions (Strombolian activity).  High lava rivers and strong earthquakes, culminating in the formation of a Plinian column that reaches a height of 13,000 meters. This eruption ends in late April 1906; elle aura duré un an. It lasted one year.  After the eruption of 1906, the peak of Vesuvius shows truncated and has a wide gap of about 500 meters in diameter and 250 deep.  The inner walls of the crater have an inclination of 40-45 ° C to about 80 feet below the rim and then to the background, they become nearly vertical.
 Moments apparent calm and violent activity will follow. The last eruption was in June 1944, or material mass of lava heading towards the village of San Sebastiano, puts to flight all the people. Elle durera 2 semaine.. It will last 2 semaine.Depuis, Vesuvius has not had any visible activity, although in remains highly active and lively.