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The Phlegraean Fields (Italian: Campi Flegrei (:ˈkampi fleˈɡrɛi); from Greek φλέγω, "to burn") are a large volcanic area situated to the west of Naples, Italy. It was declared a regional park in 2003. Lying mostly underwater, the area of the caldera comprises 24 craters and volcanic edifices. Hydrothermal activity can be observed at Lucrino, Agnano and the town of Pozzuoli. There are also effusive gaseous manifestations in the Solfatara crater, which is known as the mythological home of the Roman god of fire, Vulcan. The area also features bradyseismic phenomena, which are most evident at the Macellum of Pozzuoli which in the 18th century was misidentified as a ''Temple of Serapis'', as geologists puzzled over bands of boreholes (''Gastrochaenolites'') left by marine ''Lithophaga'' molluscs on three standing marble columns, showing that the level of the site in relation to sea level had varied. This area is monitored by the Vesuvius Observatory.〔http://www.ov.ingv.it/OV/en/campi-flegrei.html〕 == Geological phases == Three geological phases or periods are recognised and distinguished. * The First Phlegraean Period. It is thought that the eruption of the Archiflegreo volcano occurred about 39.28 ± 0.11 ka. (older estimate ~37,000 years ago), erupting about of magma ( bulk volume) to produce the Campanian Ignimbrite. "The dating of the Campanian Ignimbrite (CI) eruption to ~37,000 calendar years B.P. draws attention to the coincidence of this volcanic catastrophe and the suite of coeval, Late Pleistocene biocultural changes that occurred within and outside the Mediterranean region. These included the Middle to Upper Paleolithic cultural transition and the replacement of Neanderthal populations by anatomically modern Homo sapiens, a subject of sustained debate. No less than 150 km3 of magma were extruded in the CI eruption, the signal of which can be detected in Greenland ice cores. As widespread discontinuities in archaeological sequences are observed at or following the CI event, a significant interference with ongoing human processes in Mediterranean Europe is hypothesized." New research led by Liubov Vitalievna Golovanova and Vladimir Borisovich Doronichev of the ANO Laboratory of Prehistory in St. Petersburg, Russia, supports the hypothesis that these eruptions drove Neanderthals to extinction and cleared the way for modern humans to thrive in Europe and Asia. The area is characterised by banks of piperno and pipernoid grey tuff at Camaldoli hill, like in the northern and western ridge of Mount Cumae; other referable deep products are those found at Monte di Procida, recognizable in the cliffs of its coast. * The Second Phlegraean Period. Between the 35,000-10,500 years ago,〔 it is characterized by the yellow tuff that constitutes the rests of an immense underwater volcano (having a diameter of ca. and Pozzuoli to its center) Approximately 12,000 years ago the last major eruption occurred, forming a smaller caldera inside the main one, centered on the town of Pozzuoli. This event produced the Neapolitan yellow tuff, referring to the characteristic yellow rocks there. * The Third Phlegraean Period. Dated between 8,000 – 500 years ago,〔 it is characterized by white pozzolana, the material that forms the majority of volcanos in Flegrei Fields. Broadly speaking, it can be said there was an initial activity to the south-west in the zone of Bacoli and Baiae (10,000-8,000 years ago); an intermediate activity in an area centred between Pozzuoli, Spaccata Mountain and Agnano (8,000-3,900 years ago); and a more recent activity, moved towards the west to form Lake Avernus and Monte Nuovo (New Mountain) (3,800–500 years ago). Volcanic deposit indicating possible eruption dated Ar at 315, 205, 157 and 18.0 kya The caldera, which now is essentially at ground level, is accessible on foot. It contains a large number of fumaroles, from which steam can be seen issuing, and over 150 pools of boiling mud at last count. Several subsidiary cones and tuff craters lie within the caldera. One of these craters is filled by Lake Avernus. In 1538, an eight-day eruption in the area deposited enough material to create a new hill, Monte Nuovo. It has risen about from ground level since 1970. It is a volcano capable of producing VEI 7 eruptions, as large as that of Tambora in 1815. At present, the Campi Flegrei area comprises the Naples districts of Agnano and Fuorigrotta, the area of Pozzuoli, Bacoli, Monte di Procida, Quarto, the Phlegrean Islands (Ischia, Procida and Vivara). A 2009 journal article stated that inflation of the caldera centre in the vicinity of Pozzuoli might presage an eruptive event within decades. In 2012 the International Continental Scientific Drilling Program planned to drill 3.5 km (2.2 miles) below the earth's surface near Pompeii intending to monitor the massive molten rock chamber below in order to provide early warning of any eruption. Local scientists are worried that such drilling itself could initiate an eruption or earthquake. In 2010 the Naples city council had prevented the drilling project. Programme scientists said the drilling was no different from industrial drilling in the area. The newly elected mayor allowed the project to go forward. A Reuters article emphasized that the area could produce a "super volcano" that might kill millions.〔Antonio Denti, ("Super volcano", global danger, lurks near Pompeii ), Reuters, August 3, 2012.〕 Most recent study from Istituto Nazionale di Geofisica e Vulcanologia describing recent volcanic unrest of Campi Flegrei caldera from January 2012 to June 2013 characterised by rapid ground uplift of about with a peak rate of about per month during December 2012 mentions, that in previous years from 1985 to 2011 dynamics of ground uplift has been mostly linked to caldera's hydrothermal system. As study describes, this relation broke down in 2012 and the driving mechanism of the ground uplift changed to periodical emplacement of a magma within a flat, sill-shaped magmatic reservoir in depth cca , south from port of Pozzuoli 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Phlegraean Fields」の詳細全文を読む スポンサード リンク
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