An earthquake at 8:32:11 am PDT ( UTC−7) on Sunday, May 18, 1980, caused the entire weakened north face to slide away, a sector collapse which was the largest subaerial landslide in recorded history. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes caused by an injection of magma at shallow depth below the volcano that created a large bulge and a fracture system on the mountain's north slope. It has often been declared the most disastrous volcanic eruption in U.S. The eruption, which had a Volcanic Explosivity Index of 5, was the most significant to occur in the contiguous United States since the much smaller 1915 eruption of Lassen Peak in California. A series of phreatic blasts occurred from the summit and escalated until a major explosive eruption took place on May 18, 1980, at 8:32 am. Helens in Skamania County, Washington, United States. “The adopted scientific approach in this study reveals information that is contained in the pyroclastic deposits and that clarifies new aspects of the eruption of Pompeii and provides valuable insights for interpreting the behaviour of Vesuvius, also in terms of civil protection.On March 27, 1980, a series of volcanic explosions and pyroclastic flows began at Mount St. “It is very important to be able to reconstruct what happened during Vesuvius’s past eruptions, starting from the geological record, in order to trace the characteristics of the pyroclastic currents and the impact on population,” said Prof Pierfrancesco Dellino of the University of Bari. Today, the ruins of Pompeii are Italy’s second-most visited archaeological site, after the Colosseum in Rome and, last year, attracted about a million tourists. ![]() The resulting volcanic ashes run along the slopes of the volcano at speeds of hundreds of kilometres per hour, at high temperatures and with a high concentration of particles.” “Comparable to avalanches, they are generated by the collapse of the eruptive column. The INGV research described pyroclastic flows as “the most devastating impact” of explosive eruptions. The Pompeiians lived with earthquakes, but not with eruptions, so they were taken by surprise and swept away by that incandescent cloud of ash.” The inhabitants could not have imagined what was happening. ![]() “Those 15 minutes inside that infernal cloud must have been interminable. ![]() “It is probable that dozens of people died due to the rain of lapilli that fell on Pompeii after the eruption, but most of them died of asphyxiation,” Isaia said, adding the pyroclastic flow would have reached Pompeii a few minutes after the explosion. Isaia’s model estimates the gases, ash and volcanic particles would have engulfed the city for between 10 and 20 minutes. The study confirms that the inhabitants had no escape, and most of those who died suffocated in their homes and beds, or in the streets and squares of the city. “The aim of the work was to develop a model to try to understand and quantify the impact of pyroclastic flows on the inhabited area of Pompeii, about 10km from Vesuvius,” he added. The lethal cloud had “a temperature of over 100 degrees and was composed of CO2, chlorides, particles of incandescent ash and volcanic glass”, said Roberto Isaia, senior researcher of the Vesuvius Observatory of the INGV. The study by researchers from the Department of Earth and Geo-environmental Sciences of the University of Bari, in collaboration with the National Institute of Geophysics and Volcanology (INGV) and the British Geological Survey in Edinburgh, has revealed the duration of the so-called pyroclastic flow, a dense, fast-moving flow of solidified lava pieces, volcanic ash and hot gases that hit the ancient Roman city minutes after the volcano erupted.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |