Articolo in rivista, 2009, ENG, 10.1144/SP322.4
A. Milia; A. Raspini; M.M. Torrente
A.Milia: IAMC, CNR A. Raspini: IGG, CNR M.M. Torrente; DSGA, Università del Sannio
The interpretation of high-resolution seismic profiles acquired close the eastern coast of the Bay of Naples offshore Somma-Vesuvius volcano, and calibrated by borehole data, allowed us to recognize a reflection-free seismic facies consisting of a volcaniclastic debris avalanche overlain by pyroclastic density current deposits. Both are associated with the 3.5 ka 'Avellino eruption' and are in turn overlain by a marine succession. The top of the volcaniclastic unit corresponds to a deep erosional surface covered by a coarse-grained bioclastic layer with rounded pumice. We argue that these features are related to a tsunami that was triggered by the sudden entrance into the sea of the gigantic (>1km3) volcaniclastic unit. The onshore-offshore correlation and mapping of this volcaniclastic unit have allowed us to evaluate its distribution west of Somma-Vesuvius. The pyroclastic density current deposits terminate seaward at 40 m water depth; at the same depth the debris avalanche is affected by a gravitational instability. Over the last 3.5 ka the slump has been in constant movement, as documented by the angular unconformities at the top of the chaotic seismic unit and within the overlying marine deposits. © The Geological Society of London 2009.
Special publication - Geological Society of London 322 , pp. 105–119
debris avalanche, seismic survey, slope stability, tsunami, volcaniclastic deposit
ID: 6762
Year: 2009
Type: Articolo in rivista
Creation: 2010-03-24 00:00:00.000
Last update: 2012-04-16 16:14:34.000
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CNR OAI-PMH: oai:it.cnr:prodotti:6762
DOI: 10.1144/SP322.4