After the eruption of 7 9 AD, it falls a long silence on Vesuvius and the first news about a persistent activity ("It issues a lot of ash that reaches to the sea") is reported in 172 by Galenus, a Greek doctor that describes the properties of the dry air of the place that was created by the subterranean fires.
Cassius Dio reports a violent eruption in 203, whose explosion was heard till to Capua, that is just forty km from Vesuvius. Some news about other two large eruptions occurred in 472 and in five hundred 512 were reported by Marcellinus Comes, chancellor of the emperor Iustinianus. He refers that on 6th November 472 "A torrid mountain of Campania that burns of internals fires, has vomited the burned bowels; during the day it brought the darkness with a tiny dust on the whole surface of Europe". The eruption of 512 is described by Cassadioro, a King Teodorico’s superintendent in a letter written to ask the exemption from taxes for the people affected by the eruption. He reports that “it flies (…) a burnt ash that, after having formed clouds, it rains with dust’s drops also on the overseas provinces (…) . It’s possible to see ash’s rivers sliding like flowing liquids that drag warm sands (…) and fields’ back swell suddenly until reaching the treetops”.
An explosive eruption, occurred between 680 and 685, it’s reported by Paolo Diacono in Longobardum Historia and others are reported between 787 and 968. Leone Marsicano in the chronicles of the Abbey of Montecassino, talking about the eruption in 968, refers to "a great and unusual fire that rushed forward the sea." This eruption is perhaps the first evidence of a lava flow, defined as "resin sulphurous uninterrupted impetuously rushed towards the sea". Numerous authors speak of eruptions in 991, 993 and 999, but as that time was imbued with the conviction of an imminent end of the world, any reference to disasters should be read with a degree of suspicion. In the chronicles of Abbey of Monte Cassino it is signalled another eruption lasted six days from January 27th 1037, and an explosive event between 1608 and 1078. The last eruption, before a long period of quiescence, happens at the beginning of June 1139 and it is reported by the chronicles of Montecassino and by the chronicles of Abbazia di Cava dei Tirreni, as well as the secretary of Pope Innocent II, Falcone Beneventano, who wrote that the Vesuvius ’’threw a very powerful fire and flames for eight days long’’. There aren’t reliable testimonials on Vesuvius activities after the 1139. Around the 1360, Boccaccio writes that from the Vesuvius ’’now don’t come out neither flames nor smoke. In an unspecified year of the 1500, Ambrogio Leone da Nola reports of an eruption lasted three days, which was followed by the formation of big fumaroles. A Spanish soldier, who climbed mount Vesuvius in 1501 with queen Elizabeth, described the crater as “a hole by 25 to 30 span diameter and from which comes out continuously smoke“ that, according to some people “during the night it becomes a vivid flame”.
In 1575, Stephanus Pighius, a Belgian clergyman travelling in Italy, describes the Vesuvius “covered with vineyards, and so also the hills and the nearby fields”. Among his a chasm opens, but the volcano “is cold, neither it seems to emit no heat or smoke”. From 1500 to 1631 it is therefore certain that the Vesuvius has been inactive or nearly like that. The mountain was covered with crops and the destroyed villages had started a new life, quickly forgetting the past eruptions. Big trees were growing up to the Great cone, the cone inside the caldera of Somma, and all the system was known as the mount of Somma, from the name of the homonym city. In the night between 15 and 16 December 1631, the Vesuvius came back to life with a disastrous eruption that spread panic and destruction. From several months before, all zone was afflicted by frequent earthquakes, that were intensified the days before the eruption. Gianbattista Manso, writer of that era, describes the eruptive cloud that stand in part to the sky (plinian column) and in part, it extends on the base of the mount like a creek (pyroclastic flows). The most violent phase lasts three days and the whole eruption lasts five days, leaving trawls of mudflows and mud slips of volcanic materials accumulated on the slopes. Weak emission of ashes and earthquakes last months. After this eruption the Vesuvius changed shape: the top, that was taller than the Somma, now seems decapitated and the crater, as Bouchard says, a French scientist came up to edge of the pit, it has a diameter of 2 miles (3.5 km), compared to the previous measurement of just a mile. Going to Torre del Greco, six new volcanic pits opened. Thanks to the 1631 eruption, the Vesuvius starts a new persistent activity phase that lasts until the 1944, except for some shorts periods.
The eruption of 1944 happened a bit after allied troupes’ arrival. Because of the wars events, the Observatory has become an allies’ weather station and its director, Giuseppe Imbò, is relegated in an only room from that accomplishes his observations during the eruption days. The event takes by surprise the Americans and causes them aerial bombardment’s greater damages: a complete flock of bombers B29 that stayed in the landing field near Terzigno, was shortly destroyed by ashes. So Vesuvius seems to want to show for the last time all its power before returning to a threatening break that lasts until today. The only activity signals are some small earthquakes that are registered constantly by Vesuvius Observatory seismographs and the fumaroles activity that it is observed at the crater.
ATTACHMENTS:
- Activity of Vesuvius between 1631 and 1799
- Activity of Vesuvius between 1800 and 1899
- Activity of Vesuvius between 1900 and 1996
Foto e tabelle allegate sono tratte da: Roberto Scandone, Journal of Volcanology and geothermal Research, vol. 58, 1993