During the 79 A.D. Plinian eruption, the Lattari Mountains (a carbonateridge located 20 km south of Vesuvius) were covered by a pyroclastic layer,1 to 2.5 m in thickness. As demonstrated by widespread remants of the volcanoclasticDurece deposits, rapid erosional processes driven by steep slopessubsequently reworked the soft and loose pyroclastic material leading to(i) tens of metres of valley filling, (ii) alluvial fan growth, and (iii) fan deltaformation. Several archaeostratigraphic records scattered in the study areademonstrate that the reworking and deposition of the pyroclastic depositsoccurred over many decades and was followed by a phase of incision. Thedata collected underline the importance of carrying out careful investigationson the catastrophic impacts of explosive eruptions in areas located severalkilometres from volcanoes.
I Monti Lattari (una dorsale carbonatica a circa 20Km a sud del crateredel Vesuvio) hanno registrato la deposizione di una copertura piroclasticaspessa da 1 a 2.5m in occasione dell’eruzione pliniana del 79 d.C.Come dimostrano i molti lembi residui di depositi vulcanoclastici(Durece), i depositi di caduta della suddetta eruzione sono stati soggettia rapidi processi di erosione che hanno determinato (i) l’aggradazionedecametrica di stretti fondivalle, (ii) la riattivazione di conoidi alluvionalie (iii) la crescita di corpi sedimentari deltizi. Questa risposta è stata primariamentedovuta alle pendenze mediamente elevate dell’area di studioe all’elevata erodibilità del materiale piroclastico. Molti dati geoarcheologiciindicano che la risedimentazione dei prodotti piroclastici sia avvenutanell’arco di tempo di alcune decadi, ed è stata seguita da una rapida fasedi erosione. Questa nota sottolinea la necessità di considerare la possibilereazione catastrofica dei sistemi naturali alle eruzioni esplosive anche inaree non vulcaniche ubicate ad una certa distanza dai centri eruttivi.
Effetti catastrofici distali della eruzione del Vesuvio nel 79 d.C.: evidenze sedimentarie e geo-archeologiche in Penisola Sorrentina
ROBUSTELLI, Gaetano
2009-01-01
Abstract
During the 79 A.D. Plinian eruption, the Lattari Mountains (a carbonateridge located 20 km south of Vesuvius) were covered by a pyroclastic layer,1 to 2.5 m in thickness. As demonstrated by widespread remants of the volcanoclasticDurece deposits, rapid erosional processes driven by steep slopessubsequently reworked the soft and loose pyroclastic material leading to(i) tens of metres of valley filling, (ii) alluvial fan growth, and (iii) fan deltaformation. Several archaeostratigraphic records scattered in the study areademonstrate that the reworking and deposition of the pyroclastic depositsoccurred over many decades and was followed by a phase of incision. Thedata collected underline the importance of carrying out careful investigationson the catastrophic impacts of explosive eruptions in areas located severalkilometres from volcanoes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.